The CORRECT method has 2 adjustments.
First, disconnect the Pitman arm from the center link (I know, nobody ever does this).
First adjustment is on the steering shaft coming from the steering wheel side. Using a pull type scale (kind of like a fish scale that would measure pulling effort). Can't remember the pounds specification for steering wheel turning effort, maybe 6-8 lbs? The big nut on the outside where the shaft comes into the box. Probably won't have to adjust very much. Most people, as I previously NEVER do this adjustment. You're setting how hard it is to turn an unloaded steering wheel.
The actual adjustment you're talking about requiring loosening the lock nut where the Allen head is, 5/8" wrench I believe. You're probably going to run it in clockwise (tighten) a LITTLE bit, to get rid of slop. You can't get rid of steering play (slop) from worn tie rods, Idler arm, center link, etc., so don't go too far. You just might cause the steering box to jam up when turned off center. You can over tighten that adjustment screw very easily.
Eliminate all the worn steering parts first, then adjust the box.
Sorry if this isn't highly technical as I'm going from memory.
Just remember, if the box has lots of play, it's probably worn out and needs replacing.
