I can't recommend anyone specific, but your best bet is to find a truck repair shop that uses Hunter machines... check
here and enter your zip code.
You can obtain the latest specs and method of measurement from Spartan. Make sure they do the ride height FIRST (I've seen some shops do it backwards for some reason) and then do the alignment. Also, make sure they dump the air, reinflate and then check/adjust ride height.
Last I knew, Cummins doesn't do that type of work. The ones I've been to don't anyway.