Reading through this thread, certainly shows a massive amount of over thinking the subject.
I had a P bass in for repair yesterday. It needed a shim as the bridge saddles were all the way down and the action still too high.
Had the neck off, a piece of laminated card in there and all back together, perfectly adjusted within about thirty mins. Guess what? No loss of tone/sustain/volume and the action is just lovely now. Maybe, just maybe, the card will compress a bit in a few years time and then the whole complicated job will have to be done again.