I called up all five suppliers. I received consistent answers from all of them on: they all use the same Haartz Singletex Pinpoint vinyl material in Ford White, Doubletex was the original material, but it is either not available or too expensive to use, they all can provide the brass zipper.
Also, some can provide the strap & snap that were on later cars, some sell retail, some don't. ARO was the original supplier to Ford for convertible tops during this timeframe.
Would anyone else like to chime in on their experiences with any of these suppliers, and any "do's or don'ts" that we should know about?