[wwboater]

I just went through this last week, so my rear end only has 100 miles on it since doing.

I ended up getting the preload correct using the old nut and my impact gun. Once the preload was good I used a new nut and red loctite and torqued it to 150 foot pounds using my torque wrench. Then I rechecked the preload to make sure it was still good.

I think that if the spacer is set up correctly the preload will not shoot up drastically once you torque it, you may need less spacers.

Good luck and hopefully more folks will chime in.