x-axis dro for my vintage lathe.

[olderdan]

My SB lathe is about the same age as yours and I made a new crosslide acme screw and nut for it, an easy way too check wear is to lock the slide and measure the backlash on the feed dial at 1 inch intervals. Assuming that wear on the nut will be more of a constant than on the screw it will probably tell you that the worst area is between the C/L and about 2.5 inches out where most work is done and so the variation would be wear on the screw, this was true in my case.
However as you have done a super job of fitting a DRO you have made backlash irrelevant and given your lathe a better than new accuracy.
The reason I did not fit DRO to my lathe is that I do a lot of milling with it and so backlash is something I needed to reduce is much as possible.