Mr. Boswell has done a phenomenal job with his video's in explaining how to use saddle and Aero harness systems and I would bet he does things with his harness systems when he hunts that he doesn't show on YouTube due to potential liability issues. Hands down, Mr. Boswell does the best job in a video of explaining how to use harness systems.
The question of how to hunt larger diameter trees is relatively basic. Buy a longer rope of the exact same diameter and swap it out. True, it will void the warranty and liability, but it is only one of two ways I know of to hunt larger diameter trees and I've played with and made many alterations to these things since 1981.
I have my system altered to the point I could hunt a flat wall if I could climb it. Tree diameters mean nothing, if I can climb it, I can hunt it.
When you run into a problem, sit down and think about a solution, and find a safe remedy to the problem. We would all still be driving model A's if everyone had been perfectly satisfied with their performance. To me, problem solving with harness systems to make them more comfortable and versatile has been a challenge over the years but has also been very gratifying as long as the end solution to the problem and product remained safe.
Alterations do void warranties and liability, however the limitations built into harness systems are just that, they are safety limitations that allow a company to insure the product for liability purposes.