I did this on my 48 Ford, used Carpenter's one piece. The gasket pulled the two pieces toward each other, so I used a very small piece of rubber at both the bottom and top of the glass. I let it set for a couple of days to stretch the gasket a little. Then ran the sealer up the Vbutt. You don't want the to pieces of glass to rub.
That was 15 years ago and I've zero problems with the windshield.