Us glider folks tape over the wing/fuselage junctions, mine spends nights in a trailer where water seems no get in by the door, but not on the glider. The parachute no longer stays there
As I faintly recall, high wing Cessnas generally have a metal strip covering the wing/fuselage junction. Good luck waterproofing that
The glider folks have access to various tapes that work well and possibly will not remove the paint when they come off. But how much room is there between the cover strip and the rivet line?