Ahhhh we have an Aussie! Hiya Sparkie....I have tried all sorts of thicknesses and eventually stuck with .9mm 316. Dont ask....I just think it seems to work best, it aint cheap though. Well worth buying when you finally decide on a permanent cell to build. My plates are 75 x 120 (sorry for the decimal) and I use a +nnn-nnn+ configuration in a vacuum system. The 1/16th should work fine, make sure a/ its straight b/ trimmed and even, and c/ sand it nice and smooth in the vertical plane. Best of luck, hope to hear some progress results soon!
Cheers