Ever use RainX , it is unbelievably a great product that lets the rain roll right off, I know a bunch of folks that use it and it will let you drive in the rain
Just wax your windows with regular car wax and the water will bead off also...
The local car wash used some of the rain x treatment on my windshield once and I think they mixed it with one of the other chemicals because it would cloud when the light hit it at night... I never paid for that service there again after that... Even when they offered it free, I would pass....