Thanks Larry that was very helpful and I am now in search of 6 mm depron! (looks like rcfoam is the place to get this as they ship internationally). I am also sold on CorrosionX so I have to order some of that also.
I have some really good teflon strips that I will use for the bottom of the sponsons. They seem to be virtually indestructible and very low friction.
It will be a while before we get snow here so I have time to prepare :-)