Or just another thought, would it be easier if you split the factory windshield frame in half (cut the frame into two pieces by cutting all the way around the frame in the middle of the channel that the windshield mounts into) and weld the inner half into the car to mount the windshield in. Then use the outside half as a trim. Maybe have it chromed and use stainless screws to mount it? It would look completely original but you could use urethane to install the windshield and solve all of the wind/water leaking issues. Again maybe completely out in left field but just another thought.