TOPIC:

I am putting a Thorp Mfg. Ball Differential in my Fox. I realize this is kind of a stupid question but is there anyone who can give a little advice on how tight to set the adjustment screw? The instructions a pretty darn vague. I know I most likely will have to adjust it but the way the instructions are worded, I may have to do it 2-3 times. At least with someone's experienced advice, I could get it closer to good the first time and not have to keep taking it apart.

I have no experience with Thorp diffs, but my guess is that you have incompatible parts.
According to THIS PAGE , there are som different variants for the Fox diffs, both with and without original axles/dogbones.

Here is an extract:

4580 - Thorp Differential for Tamiya Fox (for use with stock half shafts)
4581 - Thorp Differential for Tamiya Fox (for use w/Thorp pin drive dog bones)
4582 - Adjusting Screw for 4500, 4540, 4550, 4580, 4581, 4660, 4800, 4900, 4950, 5000, 5050, 5200
4583 - L.H. Pressure Disc & Thrust Bearing Housing for 4580, 4581
4584 - R.H. Pressure Disc for 4580, 4581
4585 - Rear Axles for use with 4570 dog bones for the Falcon or FX-10 or for use with 4581 dog bones for the Fox
4586 - Dog Bones for Tamiya Fox when using 4581 Diff
4587 - Uiversals for use with Fox Stock Diff and part nos. 4585 and 4586
4588 - Complete Dog Bone and Axle Kit for stock Diff Fox (Includes: 4585, 4586 and 4587)
4590 - Turnbuckle Steering Linkage for Fox, Two Right and Left Hand Threaded Rods and Adjusting Wrench
4591 - Counter Gear for Fox
4592 - Overdrive Counter Gear for Fox

EDIT: I replied to the post before you edited, but anyway..
PS: no questions are stupid

My experience of ball diffs in buggies goes something like "Tighten it up as much as you dare without breaking something & hope it stops slipping. Then, when it keeps slipping regardless of how tight it is, tighten it some more, at which point it'll break. Then, throw it in the bin & put a gear diff in & never have problems again".
Oh no, just remembered, I've got an Astute to do at some point....