Ah good times....

Wonder what the spec for one of these axle nuts would be? Probably like the old cars with the tapered roller bearings where it’s tight enough to get the cotter pin in but not too tight and you can loosen it with hand tools.
My procedure for tapered bearings is to tighten the nut to 80lb/ft to make sure the new races are fully seated. I loosen the nut to sloppy loose and tighten till I feel a bit of drag. Then I loosen until I don't feel the drag, then one more hole looser and put in the cotter pin. That leaves room for when they heat up.

It's really a learned feel, hard to describe in print.