assuming you're working on that CH18, you can put masking tape just below where you've rounded the side panels then cut the glass when the epoxy's green, that way when you fair it the sheer will be smooth. If you want to overlap the hull a bit 1/2"-1" then you'll have a long line to fair in, which is fine if you want a 10oz glass strip at the sheer, or want to paint a line at the sheer (a good way to handle a yellow hull without having to look at it while paddling) All that glass is doing is adding a lot of ding resistance at the sheer. Glass tape would be totally unnecessary requiring lots of fairing in. You'll be surprised how tough the wood/epoxy is.