I am building a 7A Tipup and am finalizing the canopy frame. The problem I am having is the gap between the fuselage and the canopy frame (WD-725), once I put the side skirts on. The gap is uneven and at some points is as large as 6/32. I thought about aluminum shims to take up that gap, but am concerned with unsightly bends when I rivet. I am considering using some sort of filler to build up that area and sand to a good contour. Anyone use any filler in this location? What did you use? Bondo? Epoxy, carbosil, flox mixture? Fiberglass reinforced epoxy? Aluminum re-inforced filler, or just leave it and worry about it at paint time? Any suggestions would be grreatly appreciated. Thanks.