Dick makes a accurate point about stiffness. My 82" A-10 Bluefoam can qualify as a glider.
6 sq. ft plus 1.5 sq. ft. from the tail area when correctly trimmed.
I made a " pirated " performance wing by copying a Lanier U-2 foam wing. It is a thin taper wing. It also flexes so much staticly that I put a layer of Poly & Ester on the under side of the center section. Still flexes at 1# per sq. ft loading.

I then made a blue foam A-10 scale wing. Looks like a runaway drunk made the under camber too thick.

NO flex at all. With NO spars. I can HARD hand toss it into a fast, steep, flat, flared out glide.

This plane needs a powerfull toss to go to a landing 30 ' away.

Thin wing would curl up and lose lifting area as dihedral got worse.

Go thick and strong.

Pieces are larger and easier to find.