I have a NPD FG 65-66 Shelby style hood. I bought the best (most expensive) one they were offering. Surprisingly, it was flawless. I'm not used to FG pieces in such condition. Usually they require some massaging to get them close to perfect. This one needed nothing. I scratched it, primed it and painted it. Even after the clear coat, it still hasn't revealed any flaws. Maybe I just got lucky, but I've bought FG pieces from many suppliers and have NEVER had this good fortune.
The stuff marked as the best fitting glass available is just that. It comes from a specific vendor. Branda and I are buying it from the same source. I don't know about anyone else. There are several manufacturers of fiberglass out there. Just my biased 2 cents!!