Use a heavy coat of polyurethane adhesive, polyurethane is a one part epoxy that is activated by the presence of moisture. I have joined the wings and tail feathers of my last few arf kits using gorilla glue. Also using Deft Lacquer based polyurethane works great alone or with fiber mat for glassing any surface and it can be applied so thin that there is almost no weight gain. You can have almost an 1/8 of an inch or slightly more of play and a thin coat inside slot and on the jointer stab of epoxy. The joint should be stong enough, if you're doing hard g aerobatics then you should glass the joint. or double jointer the wings, with a long dowl pin further back on the wing halves. Have Fun!!!!!!!

Will