When I sheet a wing, I always start by placing a bead of glue on the leading edge of the wing only, secure it down with a length of aluminum angle stock that is clamped into place. The aluminum angle stock ensures that the clamping load is straight and even. After the glue on the leading edge dries, place glue under the remaining ribs and bend the sheeting over and clamp. Depending on the curve and wood hardness of your sheeting you may have to wet the sheeting down with a sponge. In any event, with the leading edge glued down first, I find that the rest of the glue up is easy. Hope this makes sense and helps.