I called the local limber yard today to get some prices on ext grade 3/4" plywood. I am going to pick up some to make some migratory tops. They gave me prices on 2 different kinds. 1 side ruff/1 side smooth $25 approx, 4x8. Or both sides ruff $17, 4x8. I think they called this one CD plywood. I forget now. I don't buy a lot of plywood. Which one do you buy? I am not using inner covers if that makes a difference for the ruff side.