Jay gave you good advice.
I will add, don't overthink the preload of the bearings. The measuring distance is NOT a good idea IMHO, it assumes the last guy did it right. I go by feel or recommend using the torque values.
As you tighten, the housing which is hanging loose with the yoke in the vise, will initally have slop. Like a loose wheel bearing.
As you tighten more, the slop will get less. You want zero slop, then a little preload. 20, 25 in lbs, really doesn't matter that much, just be sure there is a little drag on it without being able to feel the rollers because it is too tight.
Finally, be sure to have a good or new locknut, and a couple drops of Loctite is not bad on top of that. Once you get that drag/preload, you want it to stay that way.
Also keep in mind if you leave it in the car, you are not measuring drag of the pinion bearing preload alone, you are measuring rotating resistance of the entire pumpkin and even the axles and brakes. So the bench is the best.
In the end though, if this rear has spacers instead of crush tube, likely you will just zonk it down and it will be perfect. If it has NOTHING, which is OK too, then you need to be a little more carfeul