I'll pass on a couple of tips since I went through this two years ago. Hopefully you won't repeat my mistakes.
When I installed it two years ago on Memorial Day Weekend, I was very ambitious and tried to complete too many projects. The result is I rushed the job of installing the radar arch. Even though I used 5200, I didn't use enough of it to bed the feet of the arch to the roof. Translation: I had a leaky roof for the whole season.
Last year, I was afraid the arch would not come off because I used 5200 but it turns out I hardly used any in the first installation and the arch came off easily. When I rebedded, I used a product called Sikaflex which was recommended by the arch manufacture and liberally applied it to ensure proper bedding. SUCCESS-NO LEAKS!! :teeth
So take it from me, take your time, use the right materials, and do it right the first time because I wasn't very happy about having to do it over and I especially hated seeing the rain leak through the roof that summer. It made me feel very inept, plus I was worried that the core in the roof would be ruined. Luckily, no problems there. Needless to say, I also followed Dr. Bob's method of undercutting the core and spreading epoxy in the hole to protect against damage to the core.
Also, I agree with Rob about using the fast cure 4200 rather than the 5200. You might never know if you need to remove the arch for any reason.
Good luck with your project!