leveling tow vehicle and 5th wheel

[Nick & Gia's Trailer]

I would like to know what is the acceptable clearance between the bed rails of the tv and the 5th wheel. I currently have approximately 12" at this point.

Second part of question: I have noticed that the 5th wheel is higher in the front then rear. I cannot lower the hitch (Reese 16K with slide) as there are no more holes for adjustment up or down. The hitch comes with the square bed attachment that fits the "Pucks" in my 2013 Ford F-250 4X4 Super Duty Short Bed. After measuring the bed attachment, it raises the hitch by 5".

Third part of question: The pin box on the 5th Wheel (2013 Cougar Xlite 29RBS) still has three available bolt holes going up.

I have air bags on tv not for weight but I like the truck level when 5th wheel is attached. I only have approximately 25 -30 lbs of air in bags.

I think I covered all the bases on TV and RV information. (Approximately 6" higher in front then rear on level ground

So if I raise the pin box how will that affect the level.