Truck bed liner comes in cans as well as spray........I've used in in truck & trailer beds & ramps & bumpers. The spray doesn't coat thick enough to be solid protection, in my opinion.Three coats brushed bed liner will stand up to a lot of abuse if it has proper time to cure between coats, but it will look pretty coarse on your glass. Don't know if "asphalt look" is gonna be in this year. As for plastidip, my experience is that if it starts getting chipped, it will get really ragged quick. Have you looked into primer then several coats of enamel in black followed by clear coats? With heat to help cure, that might be the hardest finish with decent appearance. Some of the paint experts can be exact, but that's what I've done with belly pans. #m makes a good clear sheet film product that ca really provide good protection, if you can fit it to the compound curves. Let us know what you decide on, with a photo,too.