I would disagree about paint not sticking to glass very well. The last time I painted my house I thought I would not tape off the windows and just scrape of the paint later. That was a mistake, I was working my a#$ off to get it all removed. That being said I think all of these options are good. Also, if you keep your back glass clean I'm not sure anything back there is going to last very long. I say let the back cover with coralline!!!