Yes, I still have Rain-ex that I used on my Minicoopers when I lived in Canada 35 years ago.
It got me through winter rain and snow without wipers. The trick with snow was not to heat the wind shield so the snow wouldn't stick.
Driving faster actually made the rain disperse even better, and wipers just wiped off the coating sooner.
Since then, no need as I live in Southern California.
So I could get away with plexi on the Tielhol, if I could manage to fit some in a frame that contained the original compound curved glass unit.