Hello Brian.
I did a CNC conversion on a Sieg X2 clone (sold here in germany as Rothwerk EFM200).
The short form:
I use on all axis Nema23 Steppers with 3A coil current, 1.9Nm holding tork, about 72mm long from Stepperonline, toghether with a 36V / 10A power supply and Digital Stepper Drivers...