Just saw the question bout the trailing edge. I used hysol as I think most do. The very tip is a little thicker but you can sand it all uniform. If you screw it up, it's fiberglass and easy to fix. Personally, I am going to leave mine alone and just have it be a little thicker on the tip. I'll fill in and shape with polyfill to make it smooth.
Also, I think the wingtips should be removable. Every condition inspection, I would pull them off on my KF4 to inspect. You can see a lot of the wing and it's condition through the wingtip end.
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