I'm a little confused why the need for the height adjustment, unless your truck is raised above standard height.
I have a (mostly stock) 2016 F-250 which has the bed about 2" higher than the 2015 F-150, and with the Reese Titan hitch, which does have some adjustment, can tow or 2015 Rockwood fiver level (as best as I can tell using a spirit level), with over 6" clearance over the bed rails.
Actually I guess that's maybe due to the pin weight, because our fiver does have a heavier pin weight than any other "ultra light" I've seen, and thus probably drops the rear of the truck more than many others would, so a fiver with a lighter pin weight may ride higher at the front
2015 Rockwood Signature UltraLite 8281WS
2016 Ford F-250 Lariat CrewCab, 4x4, 6.2L V8