Don’t need to, Ive towed it over hill and dale and the only place I come close to contact is at the rear of the bed.
If there ever comes a time I see that hitting the side or front I’ll raise the hitch and drop a left out of my rear springs so everything stays the same.
I have about 6". I ran into a problem when I backed my unit off a narrow county road into a driveway. As my trailer turned in to the driveway, the front of my pickup turned and the front wheels dropped slightly due to the ditch. When this happened, the front of the camper hit the top of my bed. Damaged my bed cover rail. Live and learn.
On a previous 5er I had about 4" clearance with the rig sitting level. One day I noticed a small gouge in the bed rail cap. After scratching my head a bit I looked at the screws around the bottom of the 5er nose and sure enough one had black vinyl stuck to it. Not much contact but contact just the same. The gouge was about 6" forward of the tailgate so Jester's plan has some merit.
I am now running at 6"
__________________ Jim B
2017 Lariat F-350 FX4, CC, SB, 6.7 PSD 4WD
2018 MONTY 3731FL, Res Frig