I've never been able to use a dial indicator repeatably on these.
The 2 dozen or so times I've adjusted mine over the last 30 years has been the "tighten it a bit firm, then back off and pull back up a bit", based mostly on experience. The final check is to get the wheel on and grab the tire at top/bottom, and pull/push. I like to feel just a tiny but discernible click from the bearing. Turning the nut about 5-10 degrees to adjust the click to my satisfaction usually gets it right.
Works so far, got about 275k on the original bearings, with the original grease - I just stir it around a bit when I have the hub off doing rotor changes.

So, yes, they WILL apparently last forever.

Along that subject, I've observed that any genuine MB part that moves or is made of rubber will outlast any aftermarket part 10-1. Of course it costs 10x as much, too.

DG