The topic of wheelbase has come up already.
As a point of reference I used to tow a 4,100 pound 20 foot Trailmanor, a hard sided folding TT. I started out towing with a Chevy 1500HD. This is a crew cab with a short bed. I subsequently upgraded to a GMC 2500HD. This is stiffer suspension and a crew cab long bed. A world of difference. Porpoising disappeared and the built in brake controller was so much better than the Prodigy.
When it comes to wheelbase, longer is better, even for relatively small trailers.
I did not need and did not use a WD hitch.
Wayne in Coarsegold near Yosemite
2013 Forest River Solera 24R
2014 Jeep Wrangler Rubicon
ATV trailer for the following toys
2008 Yamaha WR250R,2009 Honda CRF150F
2008 Polaris Scrambler 500