I agree with Pedro. However, if you are really intent on totally encasing the coaming in glass, a trick that worked for me was to tack on the glass, cut on a bias of course, with some hot glue. If you stretch out the glass, it will conform to the lip very well. Just use a very small amount of glue, so that you don't get a cloudy spot where the glue is. In this way, my entire coaming is encased in glass.

Another trick I picked up from R/C glider builders is to use spray adhesive, such as 3M 77, to apply the glass, prior to applying epoxy. I find that spraying the glass first, then applying it like tape, works well. You can spray the coaming first instead, but you'd have to clean up the overspray afterwards.