For those of you having issues with the main door opening way too fast and slamming at the end stop, there is an easy fix. I ordered a shorter weaker shock and now it opens nice and slow without slamming the door at the fully opened end. You have to move the door's shock bracket toward the inside a little bit. By moving it to the inside and having 10 lbs instead of 20 lbs of force, it's a perfect match.
If you need video, pictures, or measurements for the bracket's relocation let me know.
BTW, if you don't want to spend 20 bucks on the shock, there is another way. You have to depressurize the shock so it becomes more of a door stop. Grab a dremel with one of the small metal cutting disks and cut a horizontal slit on the shock's shaft close to the seal. Wrap the shock on a towel (wear safety googles if you like), and press the shock so that the slit allows the oil and pressure to escape. It works well if you don't care for the door to fully open automatically.
RV Trailer Bus Van Marine Nitro Prop Gas Spring Shock Strut Lift Rep SPD 5200 10 | eBay