Looking for ward to your updates CR.
How much space is there for a ball nut for the cross slide? I have a roton ballscrew on my 7x Z axis, and have a small roton ballscrew for the X, but haven't unstalled it as there is not quite enough space. Still debating whether the mill some more space and fit it. The Acme I currently have is a PITA as I used two nuts, but they need constant backlash adjustment. The Roton nut would also have backlash, but at least it would be repeatable (hopefully).