Great thread here. I have been a mechanic for over 40 years. I originally learned how to set tow in on my dad's 73 gmc suburban. We would spin a front tire and make a line around the tire, then do the other tire and then measure front to rear on the lines and adjust. Dad used to like 0 for toe in and I did that for a long time with good results.
Fast forward a lot of years to 2020. I purchased a alignment rack for the autoshop that I supervised and decided it was time for me to fine tune my alignment abilities. I had some bad luck with alignments on my 2002 Duramax 2500 and noticed pretty bad tire wear and poor driveabiltiy. I did find a GM dealer that had a really good alignment tech who got my truck running true again after I had replaced all of the steering components. To be good at alignments is an art, and toe in is only a small part of it. The ultimate goal is driveability and tire wear. With a Jeep TJ driveability is number 1. My TJ drove like crap when I purchased it! What I found was all of my Currie Johnny Joints were worn out due to lack of grease. I replaced balls and outer urethane and got them good and tight. I set my toe close to 0 like I had always done with my solid axle 4x4's and the Jeep was still squirelly going down the road. When I received the new alignment rack at work, the first vehicle to get checked was my Jeep TJ. The first thing I noticed was my thrust angle was WAY off, close to .7 degrees by memory. My rear adjustable links were all set to even length side to side. To fix this issue I had to shorten the links on the driver side of the rear axle by close to .250 inches. Now the thrust angle was within spec. Then I double checked the axle placements by dropping a plumb bob from frame hole locations and measuring to the axle tubes. All was now good. I moved on to the front axle. Camber was slightly negative, but within spec so I left it. Caster is extremely important on a 4x4 with big tires and my caster was only about 5 degrees. I adjusted the links and got the caster close to 7 degrees. Then I moved on to toe in.
Working with the alignment machine I set my toe in close to 0 and test drove. Still had a lot of wander. I ended up close to factory spec on toe which comes out close to 3/16 when double checked with my quick trick alignment bar. Driveability is much better now but it has been a long process. I think my rock ram also adds to a little steering sensitivity due to very little steering wheel input moves the Jeep. At this point my 35 inch Mickey Thompson MTZ's are wearing very evenly.
I will add a little to this thread that after I had access to the new alignment rack I decided to align my 2017 Duramax 3500 that I had lifted the front end about 2 inches. My first attempt was a total failure! The truck pulled hard to the right going down the road. Again I tried staying close to 0 degrees of toe in, but the camber and caster kicked my butt. I learned a little bit about cross caster which involves setting the caster to a different spec on one side as opposed to the other and this can have a big effect on pulling going down the road. We don't have to worry about this on the Jeep TJ platform. When I finally WON on my truck, I set the toe in at factory spec which is fairly broad, but I went with minimum acceptable toe in and got caster and camber in spec and now my truck drives very well. What I did notice was when I had my toe set at close to zero I ended up with quite a bit of steering wander that wasn't there when I started. I will also add, that toe really doesn't seem to affect tire wear a lot, but out of spec camber will wear your tires in a hurry. I really don't care what measurement I need to go with in regard to a number like toe in. I want repeatability after I find the best setting for my vehicle that is far from stock. Find what works for your Jeep and stay with it. If you have bent something and you are 1/2 inch off on toe, fix it, but I wouldn't get hung up on the difference between 1/16-1/8-3/16, set it drive it and quit when you are happy with the results. And don't forget air pressure too on driveability. I am set on 24 psi on the road now with my 35's. More pressure equals better fuel economy, but less stability. Having a alignment rack to experiment with taught me a lot and unfortuneately some of what I learned I can't remember without looking up in a alignment manual because I don't do this every day, especially now that I am retired.