What I did last fall was to sand the final fill coat, put on a skim coat of epoxy and use the boat. I just finished the hatches and bulkheads, but still no varnish.

I was just talking to a professional canoe (FG mostly) builder and got some advice, here's my next move. Prefunctory sanding job, one reasonably good coat of high UV protectant varnish. That's it for this summer (keeping it shaded as much as I can). When things get cold, I'll sand and prep carefully (much more so than I would be inclined to do now, that's for sure...)and do a _good_ varnish job next spring (or earlier if I can locate a heated space big enough.

Best of both worlds