Yes, I am baffled regarding the detonation.  It doesn't surprise me that I have a detonation issue with the higher compression setups, but it baffles me that the 94mm engines with similar or even higher compression didn't experience detonation damage, while the 97mm engines seemed to go over the cliff at lower cranking pressures.  I understand that the flame has a bit more distance to travel, it just doesn't seem like 1.5mm on the radius would result in this problem.