RE: NOW BE HONEST....
No, the glass sheet will not do compound curves at all. But on a straight tapered wing should work like a champ. It needs to have the surface gloss sanded off, the bond to that surface is suspect if not due to residual mold release and the gloss finish.
Did you do this one with 3M-77? If so, was it completely gassed off? I've helped some foam/glass jobs by smoothing and pulling the cloth out, then tacking strategic points with thin foam-safe CA.
A layer of release film heat shrunk over it could help - that window insulating film for example. Or cut it into 2" wide ribbon, and spiral wrap the wing after glassing to smoosh it all down flat. Just some hair-brained ideas I've used in various forms in the past.
MJD