Probably not applicable to the discussion, but my wingtips are not removable so are pretty waterproof. I do have what I call doors on the tip to enclose the lights. With that in mind, there is a single drain hole at the aft edge of the fiberglass wingtip.
On the Lancair I helped with, the wings remain removable after completion and they use the tape Jeff recommends to close out the gap at the root. Consider cruise speeds at the upper end of 200 kts. and the tape should be good to go for our more modest Kitfoxes.