Oh man....I (almost) know how you feel. This sucks big time :banghead:
5200, screws, and fibertech. Removed screws like two weeks after set up.
Since the Tubbies aren't exactly molded to the contour of a ski and must be screwed on in order for it sit tight against the hull, it seems the best option is to sandwich epoxy/glass & layer over Tubbie & hull with more glass.
As someone else already mentioned, there isn't very much surface area around the lip (foam doesn't count). While I think the Tubbies II's are a better design (hydro-dynamically speaking), the Wamilton's sponson offers a better attachment design.