Very cool idea and execution! Not to be a grinch, but are you monitoring the inside? The overwhelming tendency is to over-bevel, which causes gaps on the inside, where you don't see 'em until you're stuck with 'em. Yesss, just ask me how I know.

Since I "went there", here's my remedy tip: Durham's putty. It comes in powder form in a can, just mix with water, trowel on, sand flush. It fairs out the surface easily and presents a continuous lightweight core ready for fiberglassing.