[JoeCB]

Thanks for the informative discussion. So I think that I get it … about the normally greater wear on the center main. It seems that the best procedure for an "in the car" adjustment would be as follows.
First set up the front and rear bearings to .0015 - .002 and note the amount of shims that were removed.
THEN, take that same number of shims out of the center main and just live with the slightly greater clearance at that bearing. Thus avoiding the bowing that would have resulted from going to .0015 - .002 at that center bearing.
Makes sense to me .
Joe B