From what I understand, right now, my truck has negative caster (leaning forward) and best would be more on the positive caster (towards the rear) from what I can see online and most places??

I see for caster you can rotate the shaft of the upper control arm.....but maybe also use shims to shim front or rear bolt.
Yes in the manual, I see some specific measurement for "centering" the arm...
What would be best? do a few test with just trying shims, or try to turn the shaft and do multiple tests with that too?
Its a long week-end, I have access to the shop I work at and would love to try a few things before dropping it back to the other shop that try to do the alignment and see if its at least better to shove it in their face a little.
I really want the thing to be somewhat driveable. >_<