I use a WDH (Blue Ox) on every single TT I tow, regardless of weight (or lack of it). Even with the heaviest of campers, my truck settles, but doesn't sag. In other words, it starts out tail high but settles to level. There are those that would say I don't need a WDH, but I know better.
Today's trucks are very good at staying level even with a camper hooked up, but even though they look level, the weight is still shifted around because your rear axle is now a pivot point. Using the WDH moves weight back onto the TT axles and the steer axle, making for a much better balanced rig.
With the WDH, even when towing campers as small as 17 feet long, I can tell a difference in how the trailer pulls.
I had a 2012 with air bags and they proved to be more of a PITA than they were worth where TT's were concerned. The only time they were useful was when I hooked up a 5er.
