Best replacement pistons for stock '69 engine

Mopar was famous for advertising at least a half point higher compression than there actually was. Your two barrel 318 was probably really 8 1/2-8 3/4 to one.
There are several ways to raise compression with a given piston, you can deck the block, surface the heads, and use a thinner head gasket.
That said, i hereby withdraw my recommendation for the sealed power. 7 1/2 is rediculous, too much other work, mentioned above, to get to a reasonable number.
I would shoot for a real 8 1/2 to one. Measurements and calculations required.