Cool build somehow I missed it before. Here is where I get gaskets from RA in the universal section sold by the foot. You need to measure the side profile to be sure it will work.
Body Weatherstrip Windshield Molding / Seal Parts | RockAuto
When we took out the windshield, the gasket was in superb shape - I’ll clean and soften it just a bit and reuse it. With a new GM chrome lock strip, it’ll look great. I already have my door seals with the wind lace in metallic blue as per original. Now, the tailgate seals, that’s another “what to do about this?”