I was able to get my wheel base measurements nearly the same on each side (less than 1/16" difference, and the sub is nearly centered between the pinch welds. I stopped at "nearly" because who knows how accurate the pinch welds are!

That video talks about using pins in the front alignment holes which is good, but it says nothing about using the rear alignment reference holes which are located just forward of the front leaf spring mounts. These rear reference holes are intended be used to cross measure the sub frame for square much more precisely than the pinch weld. Using the rear reference points in conjunction with the front alignment holes, I was able to square my sub to within 1/64" front to rear and side to side.

:idea: Now that's the tidbit of info I'm looking for. Thanks!