Single ball screw is out of question if you machine metals on the cnc, meaning aluminum, not steel. many though machine iron from time to time. Steel is out of question if not annealed.

1610 ball screw makes one turn and moves 10mm. so for 1mm it makes 1/10th of turn. To make one turn a 1.8 degree motor- 360/1.8=200steps per turn. When you apply 1/8 micro stepping which is the usual 200x8=1600 steps per turn.Any decent driver will do that. So to move 1mm then 1600/10=160steps per turn. 1mm/160steps=0.00625mm resolution. 1/4 microstepping will give you 0.0125 mm resolution

I would worry more about rails and ball screws parallelism and perpendicularity in all directions, as this is the culprit for the real life imprecision of a machine. Do yourself a favor and equip with precision straight edge long enough that can be laid on both the long axis rails perpendicular, and 2 precision squares, cause without this i dont see how you can even be in the <0.5mm ballpark when you reach the moment to mount everything together.