my buddy that makes t-tops buys finished fiberglass sheets, about 1/8 inch, they come gel coated on both sides, just trace out a pattern, transfer to the glass, cut it out, gel the raw edges with a paint brush and install. There used to be some one that advertised in the CCA publication that made tops out of some vynil product(had a vynil siding manufacturing business), made an ugly fishing hat out of the same material