I have a 2015 GMC 2500 and Jayco 29.5 BHDS. Front to back clearance is something you will just have to see. I was using the adapter one-way then when I changed my pin box I had to flip it around. Be very careful about the pin box the tailgate clearance. My replacement pin box was longer than my original, so I had to flip the adapter around to accommodate. I use the lowest setting for the ball. Again, just something that differs depending on trailer, pinbox and truck. I have both the factory plastic bed liner and a bed mat. Works great.
I have not had bed deflection. I have a new set of the Andersen frame rail support brackets in the box. Never installed them but I have a lite fifth wheel.