Takes a bit of careful consideration to get it right. From experience shimming is the least reliable option when an LSD is original and worn out. Most VN-VS LSD's are getting pretty old now days and the clutch cone material can become soft. In some cases when you face them and shim them the cones will just wear out in no time. This has happened to me twice One of those times was within 2000kms, and ONLY one small skid in a straight line off the lights. After the second time i vowed that every time i got an LSD, that still had original internals, i would ALWAYS replace the cones with new oversize ones. Never had a failure since.
IMO setting up an LSD is a fine art to get tolerances/ preloads/ shims etc right. SO it's worth the money to got to someone reliable to build it properly. I watched my diff guy recond mine and it's pretty tricky.