You have some good questions. Our first boat was a real lesson, and nothing went right right from the start. Down here in San Diego I chose a two part epoxy from AE Yale that was almost 1/3 the cost West's System epoxy's. Better then that, the relative viscosities and penetrating times was pretty well established, our problem was getting reliable information on epoxy thinners, mixes, etc. Acetone was the thinner of choice, though when looking the so-called experts in the eye and saying "Look at me, 'have you personally done this?'" did we get the "well, no's" So, for a sealer coat, we chose a thin penetrating epoxy, warmed both components to room temp, dragged Rikki's boat into the hot San Diego morning sun for a good sunbath, then dragged it into the garage for the sealer coat. Rikki's (and now mine) are made with recycled popular and mahogany. The sealer coat wasn't the smoothest after setting, but it did seal the wood grain, penetrate, and "kick" properly. Sanding wasn't as effective as using straight edge razors as a scraper however, the resulting finish is perhaps too smooth. But nevertheless, worked well when fiberglassed. Does anybody know what is the real epoxy thinner out there?