If I was doing it over and had a short bed truck I would give the Blue Ox Super Ride hitch a look. Lightweight with rubber cushioning to reduce shock plus it looks like it pivots on its base to provide clearance travel, however not automatically. Their website and ad copy are not the best regarding function.
I, like you, went from a TT to a 31' 5er with plenty of truck. Due to physics the shorter trailers chuck worse than the long ones and my initial tow with a B&W hitch was terrible. My solution ended up being a Hensley air hitch which is superb. I think they have a sliding adapter base now but you are stacking money on top of more money.
Sadly, the best way to know your trailer's towing dynamics is to hook it up and go. Hard to do without making a commitment to a hitch. Good luck with your decision and enjoy that 5th wheel.
