A_Camera, for those kinds of tests, you really need to use an oscilloscope, and you might want to see what happens when you put some extra load on an axis (even just lean on the Z axis as it runs), and at varying speeds.

JW, either drive would work. If you never run the motors at high speed (or not for long periods of time), then a higher voltage should not be a problem. A higher voltage would give better acceleration/performance, but the big risk is overheating the motor. That could be counteracted by reducing the current, but then you would lose torque.

You do realise that even though the DM's are high voltage drives, you still need to provide an appropriate input voltage? So the only thing you would realistically save, is a bridge rectifier and capacitor(s), as you'd still need an appropriate transformer.