I like that you tackle the pacing of crisis.
Personally I think what you want to achieve is a small turn amount for c1, the largest for c2 and a very short c3 just before ending the era. That feels the most balanced since you have 1-2 warning turns and knoiw what crisis you will face, then the main crisis which should be the longest and then the culmination which explodes but also will end the era.
