According to the old man who put my windshield in, nobody makes the dam kit that goes on after the windshield and gasket are in place. Nobody even knows what it is, or how to use it, except really old people like him of course. It is essentially a strip of butyl rubber which goes all the way around the windshield on the flange snug up against the gasket slit on that side. It is the final seal and directs water away from the gasket. The trim covers this. No matter what you do, they are pretty leak prone. If I were going to restore my car again, I would weld an extension all the way around the existing flange that I could glue the windshield to, just like a modern set up.
HOw do you spell butyl? Spell check thought I was trying to spell butler.
Sam