In post #3 Bob is saying that the tongue weight
limit is reduced by using an extended hitch. Also if sway has been a problem, an extended hitch will only make it worse.
I drive a van with a raised roof, so my trailer is completely in the wake of the van. There are no alternating vortices to generate sway:
Kármán vortex street - Wikipedia, the free encyclopedia
Due to poor packing, I have driven at highway speeds with a tongue weight
of ~30 lbs. No sway was noticed, but the trailer was pulling up as much as down. It felt really weird. I stopped at a weigh scale to check my tongue weight
, then loaded up all the water containers I had and put them in the gaucho. The trailer felt much better after that.