There's alot of options there too. I think, and I hope someone will correct me if I'm wrong, but if the fiberglass is thick enough it'll be fine. Plenty of others have done it and they don't seem to have an issue. It looks like you already have a seat there? Or maybe take a stock seat that fits in the area, strip the foam and upholstery, and extend it. Use it as a base for your custom pan.mmy problom is ggoing to be making a seat to fit nice ive seen fibberglass seat pans but how do they fit a seat ccover as surly the stapple gun will cracck the fiberglass?