I would put a rear anti-sway bar at the very top of the list of any truck I hauled a camper on. There is a reason the are called "Anti-sway bars". If I still had sway, with tears running down my cheek (due to cost) I would look at stiffer sidewall tires.
There are too many variables to state how much air you should put in air bags. It has been my experience only experimentation can determine that with each vehicle. I will add, with a split air filler setup, less sway will be encountered.
I am an absolute believer that an anti-sway bar, stiff tire sidewalls contribute the most to reducing sway. The bigger in diameter of the anti-sway bar the better.
Wayne