for starters if you spray with the wheels still on the car, I'd be very careful about spraying to much at once because you'll get runs thanks to gravity.
using the glossifier won't do anything to it in terms of making it harder to peel off, it's basically like a plasti dip clear coat. it will give it a little extra durability most likely but it shouldn't just start peelilng off on its own unless it gets chipped.
i think you need to use google a little more because a lot of these questions can easily be searched with plenty of answers out there. i know you don't want to screw up, but I get a sense of all the questions you've asked lately that you don't work on cars a lot and I foresee some "oh I screwed up" threads coming. sorry if that's harsh.