Hot Rods Speedway mailslot window frame

Anybody use one of these? If so what kind of glass and how thick did you use?
Also,one one side of glass top material will be between glass and frame,should I make a gasket of® the other side to go between glass and frame?

 

I have one on my roadster. The template they send with it is wrong. If you measure it you'll see it's out of square. It goes on the inside of the top material with no gasket material.

 

what thickness glass did you use?

 

Sorry, 1/4".

 

Thanks!