I was considering a thicker composite head gasket as suggested(0.020 to 0.040) to reduce compression, but this will certainly reduce quench, and I fear it may result in either no change, or even increase the likelihood of detonation at heavy loads.

As suggested, I will up the initial 12 degrees, and note any detonation at 36 and drop total back a bit if need be to keep it in check. But I'm also thinking if I can get away with the 160 therm verses 180 now that I have a 3 core high efficiency rad/shroud combo, plus dialing in the right octane, I may be able to keep it at 36 degrees total.

As for the carb tuning, I was very meticulous when dialing in all 3 carbs (700, 750 and 850), and definitely proved the smaller carb gave me better throttle response, quicker 0-60, slightly better 1/4 mile et's, and the same upper rpm limit of 6k.