For the most part I apply wax to my glass using a foam pad. This doesn't mean I've never used my PC 7424 though because I have. If I've been applying wax on the finish I'll give the windshield a once over with it without any issues that I can recall.
Years ago A neighbor of mine saw me waxing my glass and came over to tell me that; "you should never use wax on glass!" When I asked him why he couldn't come up with one reason. I told him I've been doing it for years without any issues at all.
Bobby How's does it stand up in the winter up here in New England with the calcium cloride they drop down on the highways like on 195 or 495 just curious. Ive always waxed my side windows on my Avalanche but not on the winshield never thought the durbility would be as got as Aquapel on my customer cars I just use rain x or Castrol waterpel and Cleaner.
Thanks Steven