Don't know if it's useful info or not (and it is totally anecdotal) but I have used the following technique a handful of times, with pinion nuts and output flanges on tcases:
iirc the advice was from ZUK, to use the same nut, and when tightening it back up pay attention to where the nut was staked, and tighten until that lines up with the notch on the pinion. That way you are very close to the torque setting that was used during the setup.
This has worked well for me. One diff I did this with has over 60k miles since we put a new seal in there. No problems or weird noises.
I have used Toyota and Marlin ecoseals with no issues.
