Like I said - I bolted the wings on because I was nervous about the wings holding location with rubber bands. Rubber gets weak if you don't change it occasionally and with a strong engine, or tumbling or flying "crazy", I didn't want the wings to go "out of sync".
Bottom wing - fill in the area behind the leading edge with balsa and then sheet it. Drill a hole for a dowel and insert. On the fuse side, you glue a 3/16 ply plate vertically cross fuse and drill a hole to match the wing dowel. Reinforce the edges with triangle stock if you're so inclined. On the trailing edge, you put another ply plate cross fuse (horizontally), build up the wing area with balsa and then sheet with 1/16 ply. Drill holes and thread the fuse plate. Done with the bottom wing - except watch your aileron linkages to make sure they have full throw. I had to cut out the fuse plate a little to get full throws.
Top wing - I filled the area behind the leading edge and in front of the trailing edges with balsa and then sheeted with 1/16" ply. Between the cabane struts, I put a 3/16" ply plate with beveled edges to match the angle of the cabanes. To insure the plate wasn't going anywhere, I pinned the plate on both sides with straight pins and then cut off the ends. I also cut off the leading and trailing edges of the cabane "forms" that normally support the wing (I'm not using rubber bands, so get rid of the weight). I drilled and tapped 4 holes (overkill I know) and then the wing bolts on. For screws, I'm using nylon 10-24s. I'll try to upload some pics later. Any questions?