A local 4x4 shop guy has a big think tube with machined surfaces he uses to line up the ends on axles. If in doubt you might visit a shop that modifies axle and see how they do it.

1955 1st GMC Suburban | 1954 GMC 250 trailer puller project | 1954 GMC 250 Hydra-Matic | 1954 Chevy 3100 . 1947 Chevy COE | and more...
It's true. I really don't do anything but browse the Internet looking for trouble...