RE: fiberglass over foam?
I ended up fiberglassing the top and bottoms and then tried to fill the weave with some spar varathane I had left over from another project but it never dried. It stayed tacky for over a week and a half so put them in the oven at 170 deg. for a few minutes trying to set the varathane but it melted the foam under the fiberglass. I built another set of floats and fiberglassed those and then tried to fill the weave with some auto spot putty I had and it melted the foam through the fiberglass. I finally just said heck with it and painted over the slightly melted floats and it is on the water again. They ended up heavier than I wanted but I was able to take off the nose wieght I had to put on before. I will see how long these last, probably quite a while, and then when I build the next set, I will just fiberglass the bottom and paint the top bare foam with foam safe paint. In fact I have to make a set of full lenth floats for my kids trainer so I will try the light and easy method on those.