Chainsaw Repair

OK, to the best I can figure

The 365SP piston is 1.5mm (.060) taller (compression height pin center to crown) than the 262XP piston.

If I want to accommodate for the piston and a squish of 0.020, I need to use a gasket that is 0.080 thick e.g. raise the cylinder off the case 0.080. Well I cannot get exactly there!

If I use 1/64 & 1/16 (0.015625 & 0.0625) that will get me to 0.078125.

If I then subtract from 0.078125 the increased height of the piston (0.060) I m left with a nominal squish estimate of .018125: not 0.020 but that is as close as I am going to get with standard gasket material.

Have I forgotten anything in my calculations?

So what do you guys think, am I chasing my til on this or what?