Just went through all this with my 73 "Cuda. One thing not mentioned was ride height. I set mine before the alignment shop visit. If that is off, the rest of the alignment will be off and alignment racks never mention it anymore.
I could not get any positive caster out of mine so I went with tubular upper arms as well.
Final alignment with the new arms was +3.5 left +3.4 right caster. Camber was -.6 left and -.7 right.
The guy did not use any canned settings but went online to research it. One of the places he looked was here on Moparts.
The results to me were astonishing, it has not handled like this in 35 years. I am very happy.
Craig.