Go to the 9 th page posting on my body repair thread and look at the second picture. You can see how a lip
Can slip under the window rubber will work. All you need to do is mount sheet metal maybe 3/8 larger in front and on the bottom so it will slip under the rubber. Call and I can explain the process if you like. Been doing it for years. Don Byers does the same thing. It works great and does not dammage the window.