Yes, Muskrat calculated head gasket, good and well. Flat-topped pistons, should be no problem. Shaped pistons, like my 9:1 domes, I drew the piston profile in AutoCad then calculated the volume of the dome. 10:1s could be real tricky. How about sticking them in clay and measuring the mould per the idea for the combustion chamber. There is just something about tipping the bike 45 deg. to get the plug hole verticle that doesn't sit well with me. Then, syringing out the liquid seems iffy.
I suppose the next issue that will come up will concern the measured PSI. So you might think 7:1 yields 7 x 14.7 (std atmos) = 102.9 PSI. I think you'll find your pressure gauge reads higher, which, I think, is due to adiabatic heating of the compressed air resulting in higher pressure. Come on you thermodynamologists, set me straight if I am wrong.
Richard L.