Far from an expert on gear setups but I started with the original pinion shim (actually used new ones as close to the old ones as I could).
I used set up bearings, strongly suggest.
Put the pinion together without the spacer.
Put the carrier in with the old shim (again, I used old ones as close as I could). I like the super shims.
If your backlash is good then run a pattern and adjust pinion depth based on that.
Recheck the pattern with the new pinion depth and adjust again as needed.
Once the pattern and measurements jive get your real bearings on and sneak up on the crush sleeve very slowly, I over crushed the first one.
Other than that I'd say make sure you have good tools and take lots of notes as you go.