Here is a pic of the Pathy hooked up to my 2008 Keystone Passport 280BH. It has a tongue weight of ~415lbs, a dry weight of 4615lbs, and a fully loaded capacity of 6050lbs.

Here is a closeup of my WDH, which is a DSP 800lb bar setup. The bars are under a fair bit of tension. When I started doing this, I would could the links from the end of the chain on the bars, and usually got 8 links. I've increase this now, and conversely increased the tension on the bars to 10 links. I've heard of people over tightening their WDHs, but I feel that this is the optimum tension for my setup.

spot the dog
Note that my trailer is perfectly level, and that the back of the Pathy is not sagged out, thanks to the Airlift 1000 and the WDH setup. Makes pulling this rig down the highway very easy.