I did the same thing on mine, just ran a zig-zag of thin ca on the inside of the sheeting to stiffen it up. Hind-sight is always 20/20, if I had to do it over again, I would have used heavier balsa sheet from my spare wood supply, but this will be fine, I really don't antisapate rough handling the wing. I'm working on the alerions right now as well, a little more work to do the robart hinge points but worth the effort, I had to make a shim set to help align the drill jig, due to the taper of the trailing edge, nothing tough though. I'll get some pic's of the progress up in a little bit, after the first alerion is done. If I can stay away from the laptop and not be distracted by things, I might have the fuse started today.