Old thread revival, but i'll had what I did. I changed the zerts (to vent air out of the accumulator assemblies on all 4 corners. That allowed me the installed a hose with a gauge and by opening the zert I would read pressure. But it was A PAIN! real good way would have been to get a small ball valve installed in which I'd screw the gauge. Really with that method it was messy and I would only see max pressure for a second, once the zert is closed, pressure is gone.
The real and good way of doing this is really simple. Get youself a ODB tactrix connector (my truck is HDJ100) and then using techstream you will be able to see pressure in all 4 corners live. SO while you sit in the truck vand look at the pressure lived on the computer, you have someone turn the torsion bars, then you lower and lift the truck and see new pressure, each time you screw, unscrew the TB, lower and lift the truck, repeat until pressure are similar and front end level. It easy and works great.
Then once you are all set and happy with the truck, height and how it drives. Next time you play with torsion bars you should use a caliper to measure thread length. So that when you remove the TB and reinstall it you simply screw it in the length you measure. Super simple and it is precise! no need to readjust with computer.