I got a new cowl to windshield seal from JC Witney,it was cheaper than 4 wheel drive.anyhow when I installed it it was kinda loose so I sealed it to the windshield with silicone sealer,Then laid down some self stick weather stripping and sealed around that with silicone sealer ....But before setting the windshield up I put down a sheet of waxed paper to keep it from adhering but to form a good gasket.you could probably use exterior calking as well /smooth out bead with soapy water and paper towels.
I do the samething with my valve cover gasket ,put silicone sealet on the valve cover apply the cork gasket and line up the holes ,put it on a sheet of wax paper, weight it down a bit and let it cure for a while.when ready to install on engine apply sealer to bottom side of gasket and bolt down.I do this because I have a steel valve cover and while tightening the bolts the gasket would squeez out.
Unfortunatley because of a blow-by problem I am blowing oil out of everywhere else.....but....not my valve cover.....LOL
Lots of luck
Learn to let go of what does not serve you ,but forces you to serve it