to lower or not lower

[wgsull]

I have a 2017 GMC 2500 Duramax and I use it to occasionally pull a 5th wheel Toy Hauler. When backing into my downward slopping driveway, the overhang of the 5th wheel comes in contact with the bedrails of my truck. I am contemplating lowering my truck and raising my 5th wheel hitch pin so there will be more space between the bed rails and the trailer. What are the pros and cons with lowering my truck?
Anyone have a better idea?