Just use the borax powder to cover the fleshy areas where the wing was removed, and pin the wing in the shape you want it. A piece of 1/4" plywood and push pins works well. If you want the natural shape, then apply the borax and let dry.
Once it dries, it will retain that shape. I use them for both simulating flydown, as well as use the wings on full strut decoys.

Don't worry about the camo gun. The lack of movement is much more important!!

If you're set on camo, I suggest having the gun dipped, or, purchasing a como shotgun. Tapes either do not work, or leave a residue.