I have to assume this is a rib and spar wood wing. I have not used the method but saw a wing for a modern pattern ship being skinned. It actually had a "bed" made out of the negative side of the ribs. The sheet was laid in the bed and the ribs were laid in and glued. I think both sides were done at the same time. The foaming polyurethane glue (gorilla glue) was used. This would be hard to do without the negative ribs.
A twist on that would be to support the training edge of the wing after the ribs are glued to the spar. I would raise the trailing edge so the wing was about "level". I would use the polyurethane glue and glue the top half of the sheeting on. When dry, flip the wing and do the bottom side. This should give you a pretty strait wing. Use magazines to weight down the sheeting while it drys.
If it is a foam wing. I still like the poly glue. It really penetrates the foam for an EXCELLENT bond. Spread the poly glue on the sheeting so the wood just looks damp. If it is shiny, you have to much glue. Both sides of the wing can be done at once or separate. Which ever you feel comfortable with. Stack back in the shucks and weight down with as much weight as you can. I like to use a 60# bag or two of softener salt.
The wing sheets should be made up first. Straiten the edges of the sheeting by cutting off the crooked part with a strait edge. Some even will make up a long sanding tool with a chunk of aluminum or steel angle. Some 80 grit sandpaper is glued to one side and the sheeting is further straitened by sanding the edge. Light sand the sheet after the glue is dry, before attaching to the wing. To edge glue the sheeting I would use yellow wood glue and keep the glue to a minimum, only enough to bond the edges. A strip of masking tape down the seam will keep the seam tight. and allow you to open it up to apply your glue. Go here for a very good tutorial on making skins. http://www.airfieldmodels.com/inform...kins/index.htm
In fact this whole site is a wealth of knowledge.
Good luck on your build and welcome back!!!