Regarding wait time, I emailed System Three. Their take is once the epoxy will 'powder' sand, i.e. not gum up the sandpaper, it's OK to varnish - say three or four days, a week is plenty. Don't know what other manufacturers would recommend for their formulation.

Concerning # of varnish coats, three seems a common starting point. The Helmsman I'm using says two, but they don't see my thin spots and enthusiastic 'tween-coat sanding. I just put the second on my hull, and it's going to want a third. Other varnishes may not build as high, and some application methods like rag wiping put down thin coats, so the number can go up. I've read numbers like seven or eight coats. Beautiful results, but I don't have that kind of patience. Maybe after she gets some water under the keel.

By the way, my first coat took a long time to dry, but the second went according to plan - a phenomenon I've heard around here before. Anyone know the chemistry on this, and if there's any remedy? No harm in waiting, but there's that patience thing again.