I also am having the same issue. I have 11" between the top of my bed and the 5th wheel. I am ordering the shorter legs from pullrite (Part # 2911). That is supposed to get 1.5" back. I haven't loaded the trailer yet but but it is very obvious that the nose is way too high and the trailer is not level. I am trying to see if they make a different pin box that does not extend as far down since I can't see any other way to close the gap between the truck and the 5th wheel. My last resort is going to be to flip the axles which will get me 4-6 inches. Let me know if you figure out any other solutions.
2014 Ram 3500 with factory towing package
2011 Attitude 37AKS
Pullrite Superglide 2900 with 4439 adapter