Missed on this combo?

You said it didn't like above 30* i assume that you tested this on the dyno? Is it possible you needed better octane of fuel to get above 30* Also what altitude do you live at, or the dyno was at.
My 408 12.75:1 compression with RHS 2.02 head with a tight Quench, wants 36 total and 22 initial @ 6600 feet with racing fuel.
Is it possible that you were getting into destination and didn't like more timing? aka need a higher octane fuel...........
Even with a super efficient combustion chamber,and i don't think you have one. 30* total seems way low.
Alu head tend to want more timing, than a cast iron head. RHS head are cast iron.