Wow! looks great! I never would have thought about doing this, but it looks great, I might have to save this thread!
Just a tip I would like to add,
http://www.uscomposites.com/ is where I get all of my fiberglass/epoxy/2 part foam from as they are the cheapest I've found. They can answer any questions about what they sell and what it will stick to, etc.. However they may not know whats "reef safe" But again, prices are nice...