Just finished glassing the seams on my SK. After glassing the interior of one side, the next morning I discovered a large lip 1/8" or more in a few areas. I just planed them even before glassing the exterior, and everything has worked out great. The other side I needed to force out areas with a stick from the inside to line them up as close as I could, planed and sanded,then I glassed the exterior first on that side. I had a semi large gap between the top and bottom near the ends, I filled with thickend epoxy before the glass went on.
good luck, don