Sure I will mention any of those 3 items
Good luck with through the glass, I had one 10+ years ago for 2 and 440, the coverage was not as good as I liked (directional lobe), but truthfully with all the repeaters now-a-days, I'm not sure it would make a difference unless you are trying to run 50w rig or are a long way from the repeater.
I am not sure about the suction cup concept, I figure if the antenna was design to be "drill a hole" type, it needs more ground plane larger than a 1-2 ft square of metal....But the wizard did say it was just a temporary mount, but modern vehicles have less and less sheet metal so it is hard... To each his own...