I used VLED's brand and love them. 5000k for whiter light. Just replaced the bulbs. No problems. Some other owners have reported computer issues with some cheap LED bulbs.
We chose as far back as possible to minimize wind noise when driving, aerodynamics, pull air through even when not running while driving and because it will be over our heads when sleeping and over the cooking area as well.
We had a local shop install our Maxxair as close to the rear as possible. You are correct to stay away from the seams. They said cutting inso the seam causes huge problems with leaking. He said the best route was to partially cut an overhead support. Lifetime warranty against leaking so I thought it was worth the $100. Picture on my Instagram page. https://www.instagram.com/p/BOchKFhjMXG/