Hey there. I’m building a 13’x7’x4’ plywood tank. I was planing on using two sheets of 3/4” glass that measured 32”x72”. By the time I had it supported properly it would only allow a 26-28” window which brings me to my question. How thick of a sheet of cast acrylic would I need to have the viewing window be 4’x8’? Or a 4’x10’? (Minus the 2-4” bracing all the way around the window). Any help would be awesome thanks.