Hello, everyone..I tried doing a search to see if it was asked before with no luck so I'll ask now. To Anybody that made their own rear wing/etc. what airfoild profile did you use? I have been looking at different profiles to use and saw the Selig S1223 has the highest CL that I could find. Does anybody know of an airfoil that has a higher lift coefficient? Here is a link to a website that shows the CD/CL vs angle of attack. The site allows you to print the profile, which I would use to make the  foam core's profile.

Ive used the exact same airfoil, the S1223, for a motorsport wing. I haven't had a chance to do any testing though but its definitely a good starting point for a motorsport wing. I have done CFD simulations and it has shown the best lift to drag ratio compared to other popular designs. It really depends on the angle of attack though.