While Waiting for my epoxy to fully cure before applying my varnish I installed all my deck lines, seat, and back rest. I hung it in my garage waiting for either a nice day or two to three weeks for the epoxy to finish cureing. well a month went buy and I still didn't manage to get it and me in the water.(thats another story that im still a little sore about it) but anyway, so I took my kayak over to the inlaws to varnish pulled all the rigging off. and there is a shadow where all the deck lines are running, I didn't have the boat in direct sun and it was hanging so the bottom would actually get more light then the top. well now I found out that flourecent lights put out some uv. and my shop is very well lit and I just changed most of my bulbs.
So Its a good Ideal if you are going to let your epoxied boat set before varnishing you probably might want to think about covering it.