The Russian aircraft of WW2 predominantly used the Clark Y, so that is easy for those scale models. The problem with the WW1 airfoils is for the most part they just were not very good. As proven by the direction Fokker went. Thickness has many advantages other than just structural integrity. Those heavily cambered thin airfoils used by the allies really created a lot of drag. Couple that with flying wires and 2 wings. I am sure there are several cheat airfoils that could be used for scale, allied, WW 1 models. The main thing I believe would be to eliminate some camber and try to get a little thicker.