Only slightly off topic... but could be useful for the OP.
For the record... the problem with CTR pistons or any high dome piston for that matter, is one of flame propogation. The flame front can be irratic due to the high dome design blocking some of the chamber floor until the piston has moved well past TDC.
ALL this can be overcome with good tuning and a cartridge wheel pointed in the right direction.
Some people won't tell their reasoning behind their dislike for CTR's... most likely because they are regurgitating something they read and don't actually understand what is happening in the chamber when the fire is lit. I think they call tem "urban myths"