Posting this for a buddy of mine as he was asking what I thought. He has a '15 F350 CC,4x4, sb,6.7 srw, air bags and Lower Stable Loads and tows a 38' +/- TH. Truck weighs 8500 and TH at 15,500. Most ...
Lower the pressure in the bags, I run 7.5 psi in mine with a 3800lb load any more than that and it lifts me off the springs too much and makes for a real bouncy ride. I would lower them 5 psi at a time until the ride improves, he might find he doesn't need the bags and just run them at their minimum pressure.
Edit to add//Also agree on upgrading stock shocks, made a huge difference on my truck.