Why not use
Tireballs and fill them with Helium... I mean, if you are looking for a way to make your ski float better this would probably be the best solution.
There is no way to become waterlogged, you can deflate and reinstall them easily, AND they can be removed for quick fiberglass repair (where normally you would have to remove the foam...).
I have been thinking about using these for awhile. They are so simple... Plus your ski will probably float after taking a sweep from an AK-47 :Banane36: