Thanks for the feedback, guys. My j30 diff already has the front bushings removed so I'm going to use this bushing kit that is allegedly made for j30 -> s13 diff swap:
https://www.enjukuracing.com/product...0-z32-s14.html
and use the j30 housing.
Hoffman, did you stack it that .80 on top of the existing shim and is there any difference for which side the shim is applied to? Assuming there is no difference, I will just apply the shim to the side that is quicker to access during disassembly. (referring to vlsd shim, not the carrier shims)