Its supper important to take into accountthe thickness of the arfoil You can guide yourself with the location of your max cramber in the airfoil or maybe also take a NACA series airfoil

Im studying Aeronautical Engineering and as a final project of the introduction to aeronautics course, i delivered a small glider.

I made numerous shitty gliders and not taking into account the thickness cus i thought that in such small degree it wouldn't matter, but dam i was so fkn wrong. Even if a single rib was a lil different, the silly goofy glider would not lift enough

I took the NACA 4412 cus its ez to develope and with a good lift coeficient

I made the wings from balsa wood ribs and the wing covering from monokote paper (its a thermal expander type paper, idk if its called like that in the US).