Thanks for the quick response.
I don't want to appear ignorant, but I'm feeling that way now. What is this "dotted line"? I've got a third party ground glass with grid markings, but no dotted lines. In my possibly broken logic, if the reducer back is centered and parallel to the larger back, it should be in in line with the tilt/swing of the larger back.
Can you recommend any documentation that may help with learning the black art of my new camera? While I've used tilt and swing in the past, they have been from the axis and not the base... and nothing asymmetric.