Here's how I set mine up....measure from rear fenderwell lip at highest point to the ground with the truck empty. Hook the trailer onto the ball without any WD stuff and measure again. Add links until the truck is as close to unloaded distance as possible without going over it.....ie....if the truck was 28" unloaded, and 24 loaded without WD.....and 3 links hanging gets it to 27" but 4 brings it to 28.5", stay with 3.
So far, so good. BTW....excellent post about the perils of believing what salespeople tell you. Too many times when we were shopping we would hear "you can tow anything on the lot". A couple of times I said, no, I can't. When the salesman replied that I could a second time, I told him to bet me $100 that a lot of the trailers were beyond my trucks published specs. He declined.
We bought a 30' TT new a couple years ago and love it, but my old 1989 F250 was near it's limits. It towed OK, and we put about 6000 miles on the combo, but this year we sprung for a 2014 Ram 2500 with the Cummins. Amazing difference in how it tows....I can imagine how the Xterra felt the first time you tried it. They're a great SUV....for what they're designed for....but towing something that heavy is beyond their capabilities.
