Just to clarify things, when I said shim up the planetaries I referred to the planetary gear set total end play, not the planetary gear sets themselves. The shim(s) go between the sun gear drive shell and rear planetary set. The factory serv. manual shows checking the gear train end play but never said anything about reducing it. There's no need having the gear sets slapping back and forth excessively.
I am not a fan of shimming the actual planetary gear sets either because like you said if their loose their worn out and shimming isn't the correct approach.
