Thanks for the response, mate.
Considering the R180 was designed for 3 plates & 2 discs each side, would removing a friction plate not compromise the clamping force of the diff'?
I know the Skyrine guys (R200's) add what looks to be a simple washer at the end of each diff case but unsure if I can do this or if I need to laser cut a friction plate looking shim?

Anyone done any R&D with this?