The only reason I bought our Reese HP trunion style with 800 lb bars for our Jayco 28RLS is to satisfy the rating of the F250's receiver. The spring bars are on their last link on the chains. Just enough to tilt the shank up in the receiver tube. The rear of the truck sits 2" lower in the rear with the trailer on the ball. The bars pick it back up 1". Front doesn't change either way.
Back in '94, we bought our first TT, 21' Aljo, to tow with our F150. We started with a hulk of a WD hitch. Then a much shorter Quality S WD hitch. Then just a ball on a short ball mount where it towed best of all.