Robert,
My method requires a dark, straight, level, isolated road.
First rule: On two lamp systems, adjust the low beams and let the high beams take care of themselves. For your four lamp system, you can adjust each bulb separately. (Great! Twice as much work. )
I unplug, or cover with cardboard, all lights except the one I'm working with. Adjust the bulb low to start.
With the single bulb illuminated, drive down the aforementioned road. If you can park on the road, that's even better. Get out and adjust the low-beam, right-left screw to put the ramp-up cutoff towards the right side of the road. Then adjust the up-down screw to put the horizontal cutoff (the top edge of the main light beam) out as far as you can without allowing the cutoff to rise above the road surface.
Then cover the other lights and make the same adjustments for the other low-beam.
Adjust the high beams to suit yourself, since you won't be blinding anyone with them. I would aim my right one a little to the right of center and the opposite with the left to get a bit wider beam.
This will work for only one condition of loading. If you load the truck, or hitch up a trailer, you will probably have to re-adjust the up-down screws. After some experimentation, I have learned how many turns it takes to compensate for the trailer.
My bottom line is that I adjust my headlights by driving the truck and setting them to suit me without blinding oncoming traffic. I'll know very quickly if I have the lights adjusted too high because oncoming traffic will flash their lights at me.
My method is not very scientific, but it works, it's very precise, and it's free.
Good luck,
Loren