New to Fifth Wheels, Couple Questions

The 6.5" was a quick measurement I took before leaving the dealers garage. Once we got out I did notice that after the first few bumps the hitch settled a little lower, maybe 1/4 to 3/8" below the line. I didn't really think too much about it as I thought I had decent clearance. Didn't think about the bag having more play at the time. Also this molding stuck down about 3/4" from where I took my measurement and I only clipped about the bottom 1/4". I'm pretty sure I knew where I happened and it was a really sharp down hill turn into a gas station. I'll remeasure everything this week once the rain let's off. I know I'll need to add air now that the camper is about loaded. I'm saying at worst my clearance shortened to 6" and I only clipped the bottom 1/4" My clearance at the moulding was 5.5" and less with the compression of the bag. Hopefully with adding more air I'll be fine but maybe not. The only thing I can adjust right now it my hitch in the truck. The pin box doesn't line up properly if it's dropped another hole, dealer tried when installing it.

As for the tonneau cover I was looking at, it was a tonno pro tri fold. I shouldn't have to worry if I switch as there are no bed rails with this tri fold. They're part of the tonneau and when it's folded up they go with it. That would add about an inch of clearance.

I ended up having to back up my entire road and had a pretty sharp turn to get in it. I could have done it better but it was my first time backing up a fw, they're quite a difference from a tt. It didn't look like it would hit my bed, however it would hit the clamps holding the tonneau cover rails on. I'll keep watching it as I don't need any other damage to anything even this minor.