RE: foam coating
Jim, I know that most guys are hesitant to break out the epoxy resin and glass cloth but once some simple skills are learned it will open up a whole new level to your modeling. For the job at hand all that one would need to do is finish sand the floats and cover them with some 2 or 3 oz fiberglass cloth. What I tell people is to think about it the same as you would if you were using Monokote. Take a sheet of cloth and lay it on the top of the float, saturate with as little amount of epoxy resin as possible. Trim any excess away with a pair of scissors and the wrap around the sides. To do that you will want to radius the corners a quarter inch or so. Next day put on a side then the other side and eventually the bottom. It takes a little time but the end result is well worth it. Once you get comfortable doing things like this you will be looking for areas in your builds to incorporate glasswork. A glassed surface is easier to paint and had great ding resistance.