Ok, I have feeler guages for measure the play (if they fit in there). Though I am still a little cloudy on where the play should be.

Where exactly do the shims go when I install them (if they were needed?). I've read through the common sites posted for reference, but I'm still unclear.

The hubs on the MU are in pretty good shape as far as I could tell by turning the dial. They had the usual scuffed/sun faded finish most all Aisin hubs have. It is a "firm smooth" with just a little catch the last 1/8-1/4" before LOCK and FREE. I planning to go through and rebuild them anyway. If they're in good shape, they'll just be in better shape.