Over inflate airbags

Congrats on thinking old school
Consider adding a 100# regulator and a hidden gauge to the circuit such as this:
https://www.grainger.com/product/SPEEDAIRE-1-4-in-General-Purpose-Air-4ZM13
Most airbags can stand 110# or so as long as you don't over extend them. Add limiting straps or chains for safety.

 

By the way you need a second electric/air valve to cut off your stock leveling valve when on high lift or it will exhaust your lift air almost as quick as you supply it.

 

Why not just adjust the leveling arm?

 

For what you're doing the leveling valve won't exhaust fast enough to matter.

 

if it is for drop and hook the second valve may not be needed for short times, I used mine for lowbed offroad type stuff.
Yes on the $3k installed that valve is $1400 off the shelf. wtf??
I guess adding a computer to a simple system to idiot-proof it maybe makes sense but....

 

Yes in this case old school with common sense can beat the he77 out of 1400 retail plus 1600 labor.