diff --git a/SourceGen/AsmGen/AsmCc65.cs b/SourceGen/AsmGen/AsmCc65.cs
index ce72463..f8c89ef 100644
--- a/SourceGen/AsmGen/AsmCc65.cs
+++ b/SourceGen/AsmGen/AsmCc65.cs
@@ -58,6 +58,11 @@ namespace SourceGen.AsmGen {
         /// </summary>
         private bool mLongLabelNewLine;
 
+        /// <summary>
+        /// Output column widths.
+        /// </summary>
+        private int[] mColumnWidths;
+
         /// <summary>
         /// Base filename.  Typically the project file name without the ".dis65" extension.
         /// </summary>
@@ -145,6 +150,10 @@ namespace SourceGen.AsmGen {
             Settings = settings;
 
             mLongLabelNewLine = Settings.GetBool(AppSettings.SRCGEN_LONG_LABEL_NEW_LINE, false);
+
+            AssemblerConfig config = AssemblerConfig.GetConfig(settings,
+                AssemblerInfo.Id.Cc65);
+            mColumnWidths = (int[])config.ColumnWidths.Clone();
         }
 
         // IGenerator
@@ -460,16 +469,17 @@ namespace SourceGen.AsmGen {
                         StringComparison.InvariantCultureIgnoreCase)) {
                 label += ':';
 
-                if (mLongLabelNewLine && label.Length >= 9) {
+                if (mLongLabelNewLine && label.Length >= mColumnWidths[0]) {
                     mOutStream.WriteLine(label);
                     label = string.Empty;
                 }
             }
 
             mLineBuilder.Clear();
-            TextUtil.AppendPaddedString(mLineBuilder, label, 9);
-            TextUtil.AppendPaddedString(mLineBuilder, opcode, 9 + 8);
-            TextUtil.AppendPaddedString(mLineBuilder, operand, 9 + 8 + 11);
+            TextUtil.AppendPaddedString(mLineBuilder, label, mColumnWidths[0]);
+            TextUtil.AppendPaddedString(mLineBuilder, opcode, mColumnWidths[0] + mColumnWidths[1]);
+            TextUtil.AppendPaddedString(mLineBuilder, operand,
+                mColumnWidths[0] + mColumnWidths[1] + mColumnWidths[2]);
             if (string.IsNullOrEmpty(comment)) {
                 // Trim trailing spaces off of opcode or operand.  If they want trailing
                 // spaces at the end of a comment, that's fine.
@@ -657,9 +667,12 @@ namespace SourceGen.AsmGen {
     /// Cross-assembler execution interface.
     /// </summary>
     public class AsmCc65 : IAssembler {
-        private List<string> PathNames { get; set; }
+        // Paths from generator.
+        private List<string> mPathNames;
+
+        // Directory to make current before executing assembler.
+        private string mWorkDirectory;
 
-        private string WorkDirectory { get; set; }
 
         // IAssembler
         public void GetExeIdentifiers(out string humanName, out string exeName) {
@@ -712,21 +725,21 @@ namespace SourceGen.AsmGen {
         // IAssembler
         public void Configure(List<string> pathNames, string workDirectory) {
             // Clone pathNames, in case the caller decides to modify the original.
-            PathNames = new List<string>(pathNames.Count);
+            mPathNames = new List<string>(pathNames.Count);
             foreach (string str in pathNames) {
-                PathNames.Add(str);
+                mPathNames.Add(str);
             }
 
-            WorkDirectory = workDirectory;
+            mWorkDirectory = workDirectory;
         }
 
         // IAssembler
         public AssemblerResults RunAssembler(BackgroundWorker worker) {
             // Reduce input file to a partial path if possible.  This is really just to make
             // what we display to the user a little easier to read.
-            string pathName = PathNames[0];
-            if (pathName.StartsWith(WorkDirectory)) {
-                pathName = pathName.Remove(0, WorkDirectory.Length + 1);
+            string pathName = mPathNames[0];
+            if (pathName.StartsWith(mWorkDirectory)) {
+                pathName = pathName.Remove(0, mWorkDirectory.Length + 1);
             } else {
                 // Unexpected, but shouldn't be a problem.
                 Debug.WriteLine("NOTE: source file is not in work directory");
@@ -742,14 +755,14 @@ namespace SourceGen.AsmGen {
             // Wrap pathname in quotes in case it has spaces.
             // (Do we need to shell-escape quotes in the pathName?)
             ShellCommand cmd = new ShellCommand(config.ExecutablePath,
-                "--target none \"" + pathName + "\"", WorkDirectory, null);
+                "--target none \"" + pathName + "\"", mWorkDirectory, null);
             cmd.Execute();
 
             // Can't really do anything with a "cancel" request.
 
             // Output filename is the input filename without the ".S".  Since the filename
             // was generated by us we can be confident in the format.
-            string outputFile = PathNames[0].Substring(0, PathNames[0].Length - 2);
+            string outputFile = mPathNames[0].Substring(0, mPathNames[0].Length - 2);
 
             return new AssemblerResults(cmd.FullCommandLine, cmd.ExitCode, cmd.Stdout,
                 cmd.Stderr, outputFile);
diff --git a/SourceGen/AsmGen/AsmMerlin32.cs b/SourceGen/AsmGen/AsmMerlin32.cs
index 8da9e7e..ef12ba7 100644
--- a/SourceGen/AsmGen/AsmMerlin32.cs
+++ b/SourceGen/AsmGen/AsmMerlin32.cs
@@ -59,6 +59,11 @@ namespace SourceGen.AsmGen {
         /// </summary>
         private bool mLongLabelNewLine;
 
+        /// <summary>
+        /// Output column widths.
+        /// </summary>
+        private int[] mColumnWidths;
+
         /// <summary>
         /// Base filename.  Typically the project file name without the ".dis65" extension.
         /// </summary>
@@ -134,6 +139,10 @@ namespace SourceGen.AsmGen {
             Settings = settings;
 
             mLongLabelNewLine = Settings.GetBool(AppSettings.SRCGEN_LONG_LABEL_NEW_LINE, false);
+
+            AssemblerConfig config = AssemblerConfig.GetConfig(settings,
+                AssemblerInfo.Id.Merlin32);
+            mColumnWidths = (int[])config.ColumnWidths.Clone();
         }
 
         // IGenerator; executes on background thread
@@ -343,7 +352,7 @@ namespace SourceGen.AsmGen {
         // IGenerator
         public void OutputLine(string label, string opcode, string operand, string comment) {
             // Split long label, but not on EQU directives (confuses the assembler).
-            if (mLongLabelNewLine && label.Length >= 9 &&
+            if (mLongLabelNewLine && label.Length >= mColumnWidths[0] &&
                     !String.Equals(opcode, sDataOpNames.EquDirective,
                         StringComparison.InvariantCultureIgnoreCase)) {
                 mOutStream.WriteLine(label);
@@ -351,9 +360,10 @@ namespace SourceGen.AsmGen {
             }
 
             mLineBuilder.Clear();
-            TextUtil.AppendPaddedString(mLineBuilder, label, 9);
-            TextUtil.AppendPaddedString(mLineBuilder, opcode, 9 + 6);
-            TextUtil.AppendPaddedString(mLineBuilder, operand, 9 + 6 + 11);
+            TextUtil.AppendPaddedString(mLineBuilder, label, mColumnWidths[0]);
+            TextUtil.AppendPaddedString(mLineBuilder, opcode, mColumnWidths[0] + mColumnWidths[1]);
+            TextUtil.AppendPaddedString(mLineBuilder, operand,
+                mColumnWidths[0] + mColumnWidths[1] + mColumnWidths[2]);
             if (string.IsNullOrEmpty(comment)) {
                 // Trim trailing spaces off of opcode or operand.  If they want trailing
                 // spaces at the end of a comment, that's fine.
@@ -604,9 +614,11 @@ namespace SourceGen.AsmGen {
     /// Cross-assembler execution interface.
     /// </summary>
     public class AsmMerlin32 : IAssembler {
-        private List<string> PathNames { get; set; }
+        // Paths from generator.
+        private List<string> mPathNames;
 
-        private string WorkDirectory { get; set; }
+        // Directory to make current before executing assembler.
+        private string mWorkDirectory;
 
 
         // IAssembler
@@ -659,21 +671,21 @@ namespace SourceGen.AsmGen {
         // IAssembler
         public void Configure(List<string> pathNames, string workDirectory) {
             // Clone pathNames, in case the caller decides to modify the original.
-            PathNames = new List<string>(pathNames.Count);
+            mPathNames = new List<string>(pathNames.Count);
             foreach (string str in pathNames) {
-                PathNames.Add(str);
+                mPathNames.Add(str);
             }
 
-            WorkDirectory = workDirectory;
+            mWorkDirectory = workDirectory;
         }
 
         // IAssembler
         public AssemblerResults RunAssembler(BackgroundWorker worker) {
             // Reduce input file to a partial path if possible.  This is really just to make
             // what we display to the user a little easier to read.
-            string pathName = PathNames[0];
-            if (pathName.StartsWith(WorkDirectory)) {
-                pathName = pathName.Remove(0, WorkDirectory.Length + 1);
+            string pathName = mPathNames[0];
+            if (pathName.StartsWith(mWorkDirectory)) {
+                pathName = pathName.Remove(0, mWorkDirectory.Length + 1);
             } else {
                 // Unexpected, but shouldn't be a problem.
                 Debug.WriteLine("NOTE: source file is not in work directory");
@@ -689,14 +701,14 @@ namespace SourceGen.AsmGen {
             // Wrap pathname in quotes in case it has spaces.
             // (Do we need to shell-escape quotes in the pathName?)
             ShellCommand cmd = new ShellCommand(config.ExecutablePath, ". \"" + pathName + "\"",
-                WorkDirectory, null);
+                mWorkDirectory, null);
             cmd.Execute();
 
             // Can't really do anything with a "cancel" request.
 
             // Output filename is the input filename without the ".S".  Since the filename
             // was generated by us we can be confident in the format.
-            string outputFile = PathNames[0].Substring(0, PathNames[0].Length - 2);
+            string outputFile = mPathNames[0].Substring(0, mPathNames[0].Length - 2);
 
             return new AssemblerResults(cmd.FullCommandLine, cmd.ExitCode, cmd.Stdout,
                 cmd.Stderr, outputFile);
diff --git a/SourceGen/AsmGen/IAssembler.cs b/SourceGen/AsmGen/IAssembler.cs
index 2de7a84..bbf7167 100644
--- a/SourceGen/AsmGen/IAssembler.cs
+++ b/SourceGen/AsmGen/IAssembler.cs
@@ -37,7 +37,8 @@ namespace SourceGen.AsmGen {
         AssemblerConfig GetDefaultConfig();
 
         /// <summary>
-        /// Queries the assembler for its version.
+        /// Queries the assembler for its version.  Assembler executable paths are queried from
+        /// the global settings object.
         /// </summary>
         /// <returns>Assembler version info, or null if query failed.</returns>
         AssemblerVersion QueryVersion();
diff --git a/SourceGen/Tests/GenTest.cs b/SourceGen/Tests/GenTest.cs
index c8a2650..a13ea07 100644
--- a/SourceGen/Tests/GenTest.cs
+++ b/SourceGen/Tests/GenTest.cs
@@ -387,10 +387,21 @@ namespace SourceGen.Tests {
             // it for the localization test.
             settings.SetBool(AppSettings.SRCGEN_DISABLE_LABEL_LOCALIZATION, true);
 
-            // We will also want to define (or remove to get default behavior) any
-            // assembler-specific stuff that affects generated output, like column widths.
-            // We need to retain the assembler-specific configuration for things like
-            // where the assembler shell command lives.
+            IEnumerator<AssemblerInfo> iter = AssemblerInfo.GetInfoEnumerator();
+            while (iter.MoveNext()) {
+                AssemblerInfo.Id asmId = iter.Current.AssemblerId;
+                AssemblerConfig curConfig =
+                    AssemblerConfig.GetConfig(settings, asmId);
+                AssemblerConfig defConfig =
+                    AssemblerInfo.GetAssembler(asmId).GetDefaultConfig();
+
+                // Merge the two together.  We want the default assembler config for most
+                // things, but the executable path from the current config.
+                defConfig.ExecutablePath = curConfig.ExecutablePath;
+
+                // Write it into the test settings.
+                AssemblerConfig.SetConfig(settings, asmId, defConfig);
+            }
 
             return settings;
         }