I did manage to setup a Wilwood kit with OEM bearings a few years back, but I had to have someone fabricate a metal piece on a lathe to put inside the diff, between the two axles, so they could butt against each other (tapered bearings equalize the load on both wheel bearings, so you need to be able to tighten the axles together to almost zero lash).
The Wilwood aluminum flanges added a lot of distance compared to the drum backing plates, so much the adjuster could not be used alone to correct this. If you're having new axles custom made, you can add the difference to their length.

If I had to do it again though, I'd go with a kit from DrDiff, as :
- The Wilwood inner drums for a parking brake are a joke, they do not brake worth a damn, and the aluminum flange can bend *very* easily.
- Everything I've ever bought from DrDiff was top notch, *really* bolt-on stuff.