I have been using
http://www.bateau2.com out of vero, their prices are good, and tech support is excellent. I don't know what they have in glass resin, they specialize in epoxy/stitch and glue boats. I don't think I would ever use glass resin again for anything but building caps, livewells, etc. I alwalys use expoxy now for coring, repair, or structural work. It cost a little more, but the strength, ease of use, and lack of fumes makes it the only choice for me.