NJ,
Trust me, the rubber band is plenty enough to hold the wings together. I use a zip tie to hold my wings together because I transport my plane assembled so the wings stay on my plane for weeks if not months at a time. One time while working on it in the pits I forgot to replace the zip tie and took off. On a pass over the field a friend mentioned that something didn't look quite right, so I landed. Once on the ground the "not quite right" was the right wing section sliding off about 1/2". I was lucky to not lose it, but the point I'm making is there isn't a whole lot of force to pull the wings off of the tubes. Use a rubber band and you'll be just fine.