If you are designing a wing skin of glass, why not make skin 3 plies of 7781, with first ply down a 0/90 for bending strength and next ply +/- 45 for torsional strength and third ply another 0/90 for additional bending? 7781 is 10 mils thick, close to equal warp and fill count and is cheap. It would eliminate any standoff as woven fabric is smooth.
Bob H