Thank everyone for the reply!
I just check my squish on my two drag bike.
1) 4 mill stock cylinder pd 18cc machined (0,080) for the extra strock, 0,010 gasket, squish : 0,057 but not enought place into the center of the dome ( i'm about 210 psi)
2) stock stroke, pd18cc unmachined, 0,010 gasket squish : 0,047, i'm at 180 psi
I think i have to much squish, what do you think?