Haven't really decided on a covering, I like the glass as it's already fuel and water proof, with the balsa, I would still have to finish. I may just whip out a pair and try them unfinished, just the bare blue foam with a little tape on the planing surface, that way I can try a couple of different mount positions, and widths without spending much $$$ and time wise. I got a 4X8' piece of 1.5" foam, so I can use two pieces to get 3", or if I really need 4", I can put a 1" piece in the center. I stuck a 3" wide float in the water last night that I cut from junk foam, it suported 5.5lb(not counting it's weight) on the step just before the tail went under, so I think I will have plenty of boyancy for a 5.5lb plane with two floats. Do you base your 4" recomendation on flotation, or getting it up on plane?

Ken