Yup, it's trial and error at best once parts start getting swapped. I run non-stock leaf springs and have a 3.91 rear end, so it takes an extra 3 degrees down from theoretical 'right' to run smooth uphill. Then I added assassin bars, and had to reset once again LOL.
I think it's more important for people to understand why the angle across the joint needs to be equal in the first place, helps visualize what's going on. In this day and age, I think folks would benefit from trying to stick a camera or phone under the car to take a video of the axle wrap during a quick drive. With some creativity, it could be used to really dial-in what's required.
