Definately glue the rectangle stock on first; that way you're assured to have enough wood on the topm and bottom to form. AFter drying, assuming, perhaps it is planked, rough-form it with the pre-mentioned plane, then you could lightly hold the wing between your legs, take 1 foot or so lenght of 150 grit sand paper, and lightly sand it perpandicular to the grain back and forth working your way down the L.E. you'll be able to alter the pressure and radius by viewing how close you're getting to the planking on both top and bottom.