I'm pretty sure that nash had woosner, with loads of trouble, ended up having to rebuild engine due to the pistons, noise and wear.
I assume(hope) you're going naturally aspirated if wanting 12:1, but not mentioned, forget 12:1 with a turbo, if sticking with turbo then the std mahle are excellent, people using these at 500bhp, my own ones did 200,000 miles!!
As to size there was 2 sizes used on the Yb engines, where the marking is by the dizzy clamp the numbers 2 or 3 relate to the pistons in that position with 2 being size 90.758-90.772mm, size 3 is 90.768-90.782mm, the important thing is the bore clearance but new pistons will be around 0.035mm - 0.062mm, you need to measure the bore wear first, my engine at 200,000 miles nearly missed the 1st oversize and jumped direct to 2nd oversize due to wear!!
tabetha