I try and bench with an arch, although my arch isn't really that good. I had benched 275 raw, but to be honest i bet my raw strength wasn't that high on meet day.
So technically i may have been getting more than 75lbs out of the shirt, and the shirt wasn't really as tight as it should have been. But i dunno if i could get much more out of it, 350 was a grinder all the way from the bottom, which usually in my shirt i get alot of rebound off my chest and just carry it through to lockout, but not when i hit 350, so i dunno.
I'm going to be using a double ply F6 at my next meet, so i probably wont be using the single ply anymore.