Tom,
I have a 3 jaw mounted on my RT so the weight is at or above my ability to safely move it to and from the mill table and most of the time I have the vise mounted so that save me from the change out.
Here is something I learned from watching one of tom liptons videos of a similar topic-
For a bolt circle on a rotary table, the larger the diameter the more potential error introduced if the angle is not perfect. On the DRO, it wouldn't make any difference how large the circle was.
Another way to think about this comes from aircraft VOR navigation. At a radius of 60 miles from the transmitter station, a one degree deviation would put you off course by one mile. That would be a really large bolt circle, so probably not a concern.
Keep in mind that I only pretend to know much about this stuff!
Jim