diff --git a/M6502/HarteTest_6502/byte_t.cpp b/M6502/HarteTest_6502/byte_t.cpp
index ff8b4de..fcb9d11 100644
--- a/M6502/HarteTest_6502/byte_t.cpp
+++ b/M6502/HarteTest_6502/byte_t.cpp
@@ -8,21 +8,50 @@
 byte_t::byte_t(simdjson::dom::element input) noexcept
 : byte_t(input.get_array()) {}
 
+#ifdef JSON_ACCESS_DATA_VIA_OBJECT
+
+byte_t::byte_t(simdjson::dom::array input) noexcept
+: m_raw(input) {}
+
+#else // JSON_ACCESS_DATA_VIA_OBJECT
+
+#ifdef JSON_PREFER_ITERATOR_TO_INDEX
+
+byte_t::byte_t(simdjson::dom::array input) noexcept {
+    assert(input.size() == 2);
+    auto iterator = input.begin();
+    m_address = (uint16_t)(int64_t)*iterator;
+    m_value = (uint8_t)(int64_t)*++iterator;
+}
+
+#else // JSON_PREFER_ITERATOR_TO_INDEX
+
 byte_t::byte_t(simdjson::dom::array input) noexcept
 : m_address((uint16_t)(int64_t)input.at(0)),
   m_value((uint8_t)(int64_t)input.at(1)) {
     assert(input.size() == 2);
 }
 
-#endif
+#endif // JSON_PREFER_ITERATOR_TO_INDEX
+
+#endif // JSON_ACCESS_DATA_VIA_OBJECT
+
+#endif // USE_SIMDJSON_JSON
 
 #ifdef USE_RAPIDJSON_JSON
 
+#ifdef JSON_ACCESS_DATA_VIA_OBJECT
+
+byte_t::byte_t(const rapidjson::Value& input)
+: m_raw(input) {}
+
+#else
+
 byte_t::byte_t(const rapidjson::Value& input)
 : m_address((uint16_t)input[0].GetInt64()),
-  m_value((uint8_t)input[1].GetInt64()) {
-    assert(input.Size() == 2);
-}
+  m_value((uint8_t)input[1].GetInt64()) {}
+
+#endif
 
 #endif
 
@@ -31,26 +60,53 @@ byte_t::byte_t(const rapidjson::Value& input)
 byte_t::byte_t(const boost::json::value& input) noexcept
 : byte_t(input.get_array()) {}
 
+
+#ifdef JSON_ACCESS_DATA_VIA_OBJECT
+
+byte_t::byte_t(const boost::json::array& input) noexcept
+: m_raw(input) {}
+
+#else
+
 byte_t::byte_t(const boost::json::array& input) noexcept
 : m_address((uint16_t)input[0].get_int64()),
   m_value((uint8_t)input[1].get_int64()) {
     assert(input.size() == 2);
-};
+}
+
+#endif
 
 #endif
 
 #ifdef USE_NLOHMANN_JSON
 
+#ifdef JSON_ACCESS_DATA_VIA_OBJECT
+
+byte_t::byte_t(const nlohmann::json& input) noexcept
+: m_raw(input) {}
+
+#else
+
 byte_t::byte_t(const nlohmann::json& input) noexcept
 : m_address(input[0].get<uint16_t>()),
   m_value(input[1].get<uint8_t>()) {
     assert(input.size() == 2);
 }
 
+#endif
+
+
 #endif
 
 #ifdef USE_JSONCPP_JSON
 
+#ifdef JSON_ACCESS_DATA_VIA_OBJECT
+
+byte_t::byte_t(const Json::Value& input)
+: m_raw(input) {}
+
+#else
+
 byte_t::byte_t(const Json::Value& input)
 : m_address((uint16_t)input[0].asInt64()),
   m_value((uint8_t)input[1].asInt64()) {
@@ -58,3 +114,5 @@ byte_t::byte_t(const Json::Value& input)
 }
 
 #endif
+
+#endif
diff --git a/M6502/HarteTest_6502/byte_t.h b/M6502/HarteTest_6502/byte_t.h
index 071becb..44dd9ba 100644
--- a/M6502/HarteTest_6502/byte_t.h
+++ b/M6502/HarteTest_6502/byte_t.h
@@ -24,9 +24,36 @@
 
 class byte_t final {
 private:
+
+#ifdef JSON_ACCESS_DATA_VIA_OBJECT
+
+#ifdef USE_SIMDJSON_JSON
+	simdjson::dom::array m_raw;
+#endif
+
+#ifdef USE_RAPIDJSON_JSON
+	const rapidjson::Value& m_raw;
+#endif
+
+#ifdef USE_BOOST_JSON
+	const boost::json::array& m_raw;
+#endif
+
+#ifdef USE_NLOHMANN_JSON
+	const nlohmann::json& m_raw;
+#endif
+
+#ifdef USE_JSONCPP_JSON
+	const Json::Value& m_raw;
+#endif
+
+#else
+
 	uint16_t m_address = 0xffff;
 	uint8_t m_value = 0xff;
 
+#endif
+
 public:
 
 #ifdef USE_SIMDJSON_JSON
@@ -51,7 +78,29 @@ public:
 	byte_t(const Json::Value& input);
 #endif
 
+#ifdef JSON_ACCESS_DATA_VIA_OBJECT
+#ifdef USE_SIMDJSON_JSON
+	[[nodiscard]] auto address() const noexcept { return (uint16_t)(int64_t)*m_raw.begin(); }
+	[[nodiscard]] auto value() const noexcept { return (uint8_t)(int64_t)m_raw.at(1); }
+#endif
+#ifdef USE_RAPIDJSON_JSON
+	[[nodiscard]] auto address() const noexcept { return (uint16_t)m_raw[0].GetInt64(); }
+	[[nodiscard]] auto value() const noexcept { return (uint8_t)m_raw[1].GetInt64(); }
+#endif
+#ifdef USE_BOOST_JSON
+	[[nodiscard]] auto address() const noexcept { return (uint16_t)m_raw[0].get_int64(); }
+	[[nodiscard]] auto value() const noexcept { return (uint8_t)m_raw[1].get_int64(); }
+#endif
+#ifdef USE_NLOHMANN_JSON
+	[[nodiscard]] auto address() const noexcept { return m_raw[0].get<uint16_t>(); }
+	[[nodiscard]] auto value() const noexcept { return m_raw[1].get<uint8_t>(); }
+#endif
+#ifdef USE_JSONCPP_JSON
+	[[nodiscard]] auto address() const noexcept { return (uint16_t)m_raw[0].asInt64(); }
+	[[nodiscard]] auto value() const noexcept { return (uint8_t)m_raw[1].asInt64(); }
+#endif
+#else
 	[[nodiscard]] constexpr auto address() const noexcept { return m_address; }
 	[[nodiscard]] constexpr auto value() const noexcept { return m_value; }
+#endif
 };
-
diff --git a/M6502/HarteTest_6502/cycle_t.cpp b/M6502/HarteTest_6502/cycle_t.cpp
index bd0ecef..66160e2 100644
--- a/M6502/HarteTest_6502/cycle_t.cpp
+++ b/M6502/HarteTest_6502/cycle_t.cpp
@@ -29,6 +29,18 @@ cycle_t::cycle_t(uint16_t address, uint8_t value, action_t action) noexcept
 cycle_t::cycle_t(simdjson::dom::element input) noexcept
 : cycle_t(input.get_array()) {}
 
+#ifdef JSON_PREFER_ITERATOR_TO_INDEX
+
+cycle_t::cycle_t(simdjson::dom::array input) noexcept {
+    assert(input.size() == 3);
+    auto iterator = input.begin();
+    m_address = (uint16_t)(int64_t)*iterator;
+    m_value = (uint8_t)(int64_t)*++iterator;
+    m_action = to_action((std::string)*++iterator);
+}
+
+#else
+
 cycle_t::cycle_t(simdjson::dom::array input) noexcept
 : m_address((uint16_t)(int64_t)input.at(0)),
   m_value((uint8_t)(int64_t)input.at(1)),
@@ -38,14 +50,14 @@ cycle_t::cycle_t(simdjson::dom::array input) noexcept
 
 #endif
 
+#endif
+
 #ifdef USE_RAPIDJSON_JSON
 
 cycle_t::cycle_t(const rapidjson::Value& input)
 : m_address((uint16_t)input[0].GetInt64()),
   m_value((uint8_t)input[1].GetInt64()),
-  m_action(to_action(input[2].GetString())) {
-    assert(input.Size() == 3);
-}
+  m_action(to_action(input[2].GetString())) {}
 
 #endif
 
diff --git a/M6502/HarteTest_6502/state_t.cpp b/M6502/HarteTest_6502/state_t.cpp
index c078205..f499d1c 100644
--- a/M6502/HarteTest_6502/state_t.cpp
+++ b/M6502/HarteTest_6502/state_t.cpp
@@ -60,12 +60,12 @@ state_t::state_t(const nlohmann::json& serialised)
 #ifdef USE_JSONCPP_JSON
 
 state_t::state_t(const Json::Value& serialised)
-: m_pc(serialised["pc"].asInt64()),
-  m_s(serialised["s"].asInt64()),
-  m_a(serialised["a"].asInt64()),
-  m_x(serialised["x"].asInt64()),
-  m_y(serialised["y"].asInt64()),
-  m_p(serialised["p"].asInt64()),
+: m_pc((uint16_t)serialised["pc"].asInt64()),
+  m_s((uint8_t)serialised["s"].asInt64()),
+  m_a((uint8_t)serialised["a"].asInt64()),
+  m_x((uint8_t)serialised["x"].asInt64()),
+  m_y((uint8_t)serialised["y"].asInt64()),
+  m_p((uint8_t)serialised["p"].asInt64()),
   m_ram(serialised["ram"]) {}
 
 #endif
diff --git a/M6502/HarteTest_6502/stdafx.h b/M6502/HarteTest_6502/stdafx.h
index 5d1d31e..ee68a04 100644
--- a/M6502/HarteTest_6502/stdafx.h
+++ b/M6502/HarteTest_6502/stdafx.h
@@ -26,12 +26,14 @@
 #define USE_SIMDJSON_JSON	// 13 seconds (19)
 //#define USE_RAPIDJSON_JSON	// 19 seconds (22)
 //#define USE_BOOST_JSON	// 26 seconds (32)
-//#define USE_NLOHMANN_JSON	// 56 seconds (69)
-//#define USE_JSONCPP_JSON	// 80 seconds (91)
+//#define USE_NLOHMANN_JSON	// 56 seconds (65)
+//#define USE_JSONCPP_JSON	// 80 seconds (87)
 
 #ifdef USE_SIMDJSON_JSON
 #	define JSON_PREFER_PASS_BY_VALUE
 #	define JSON_PREFER_REUSE_OF_PARSER
+#	define JSON_PREFER_ITERATOR_TO_INDEX
+#	define JSON_ACCESS_DATA_VIA_OBJECT
 #	include "simdjson/simdjson.h"
 #endif
 
@@ -39,19 +41,23 @@
 #	define RAPIDJSON_HAS_STDSTRING	1
 #	define RAPIDJSON_SSE42
 #	define JSON_INSITU_PARSE
+#	define JSON_ACCESS_DATA_VIA_OBJECT
 #   include "rapidjson/document.h"
 #endif
 
 #ifdef USE_BOOST_JSON
+#	define JSON_ACCESS_DATA_VIA_OBJECT
 #	include <boost/json.hpp>
 #endif
 
 #ifdef USE_NLOHMANN_JSON
 #	define JSON_USE_IMPLICIT_CONVERSIONS 0
+#	define JSON_ACCESS_DATA_VIA_OBJECT
 #	include "nlohmann/json.hpp"
 #endif
 
 #ifdef USE_JSONCPP_JSON
 #	define JSON_PREFER_REUSE_OF_PARSER
+#	define JSON_ACCESS_DATA_VIA_OBJECT
 #	include <json/json.h>
 #endif