There is no "right" answer for this. It's going to depend on how your 5er rides, and the road conditions. Ideally, what you're looking for is just enough air to level the truck. On my current truck, 25psi levels the truck. But for the horrible cement roads of Houston, I have to go to nearly 45psi to take the chucking out enough to feel comfortable. I can then lower the psi to 35 or 30 for a good ride on most roads.
On my old truck, it took nearly 50psi to level the truck, and I road with 60 - 70 almost everywhere I drove.
So, it's going to take some experimenting on your part. One thing I learned from from the old truck going to the new one...the Airlift Wireless Air Compressor is awesome. It will let you adjust the psi on the fly. That's the way to go!
Ed and Sharon
2010 Wildcat 28RKBS
2011 Ford F-250 XLT, 6.7L PSD
Ride-Rite Airbags and Airlift wireless remote compressor...nice!
I thought I was wrong once, but I was wrong!