Proper ride height 2017 prostar

What is the proper ride height for 2017 prostar,i am getting vibrations 45-75,seems to vibrate less when going uphill,i had the mechanic check everything and he couldnt find anything,i have new kingpines,steer tires, alignment,balanced all tires and still the same so probably ride height is what is causing driveshaft to work at an angle.

 

This is what i found online,leveling valve is made by hadley on this truck

 

Not sure,ill take a pic tommorow.
If it vibrates less when going uphill then it needs more air right bcos when you go uphill system pumps more air into rear airbags when on on an incline?

 

Looks like ubolt and bump stop are touching on all 4 corners

 

My leveling valve shouldnt be pointing up,it should be perfectly level i think this is the problem,going to try to adjust tommorow or buy adjustable linkage

 

Just measured it with engine on,parking brake released and on level surface,im about half an inch under 2.75