Personally, I think you should epoxy and varnish an hour or two before the race, then set the boat in mud to cure. (Okay, so what if I am entered in the same race? The wicked good Run of the Charles.)
Last year, I threw on the last coat of varnish about 24 hours before the race, and everything seemed fine. Worse comes to worse, you can put another coat of varnish on a week or so after the event.
See you race day. I'll be the guy in the Pygmy Osprey HP, probably entering the 9-mile event (19-miles is still a bit much for me.)
Grambo

: I do a 60,000 mile overhaul every year. Dings, scrapes into the glass just
: need to be filled with epoxy. However, they may not wet out and remain
: white. I mix some varnish with stain and try to match the scratch area to
: the surrounding color if this happens with an artist brush - usually on
: the bottom.

: As far as wether to sand it all off is up to you. I wouldn't - but if you use
: 100 grit for starters, you can remove most of it in no time and finish up
: with fine grits - you know the drill. Only you know how bad the boat
: really looks.

: I always try to get down to glass when epoxying. I don't think it hurts if
: the epoxy goes over a feathered varnish edge.

: You can throw it in the water the following day after a varnish. I would give
: it two. Don't forget, varn takes weeks to fully dry - so it's always in
: progress-you can smell it. This all depends on how warm your drying area
: is.

: I'd let epoxy cure for at least 4 days (warm) before varnishing over it and
: scrub it with a scotch bright pad and soap and water to remove blush. I've
: always paddled my kayaks with just epoxy and no varn. to try them. Nothing
: horrible'is going to happen. I'd rather wait till it's really out-gassed
: before varnishing - like a week on new boat.