I get skeptical every time someone wants to raise compression but does nothing to strengthen the bottom end.
The 350 has an advantage here over the 500, in that the bottom end is as strong as a 500, but with a much lighter piston. Generally, I shorten the barrels by 2mm, from the base, this work reduces the combustion chamber volume by about 8cc on its' own at TDC with whatever piston is in place. Doing this and fitting a Meteor Minor Sports piston [big dome, see pic] will still only give around 9.5:1 C.R., something I have done many times. The 350 really wakes up at around 10:1, but the cutaway for the inlet valve in the piston crown, whatever piston is used will usually need cutting a bit deeper, once 2mm removed from the barrel base is exceeded and any head gasket done away with. The rewards for this extra hassle are well worth it, though, with a big increase in go for that extra 0.5:1 or so hike in compression!
Although from our racing projects, pictured below [on the left] is a Meteor Minor Sports piston. There are a few 350 Bullets in the U.K. [and one in France] using these
B.W.