Bob posted two sources for fiberglass sheet..a potentially good idea.. but a key problem is how to form a large enough laminate for a hardtop. For example my top was 9ft x 9ft and I used four pieces of 5ft x 10ft 3/16" thick marine plywood...(placed side by side each pair was 10ft x 10ft before trimming) so I was able to epoxy them with one layer of two sheets (side by side) forward and aft, the other layer of two sheets (side by side)athwarthsips for strength. In other words, the seams of the top and bottom layer were offset for strength. You'll need to plan how to arrange smaller pieces to fit your top dimensions. Also, a layer of plywood laminate between thin glass covering will be lighter than solid glass although the latter may well be more durable. Some of those solid glass pieces appear a bit heavy at 2 lbs per sq ft if laminated. Finally, be sure you plan how to make edges for the hardtop for looks, rigidity, and ability to protect the soft curtain to hardtop seam from direct wind and rain....yes!!!! ...wind driven rain will be blown through the channel slot favored for the soft cover to hardtop joint...Curves make for an appealing profile but require a lot of work unless the proper shapes can be purchased...