Current favourite stepper drivers

[JAZZCNC]

Graeme clive is correct that AM882 are the way to go but to answer your questions about current and Voltage. Out of the two having higher safety margin on voltage is most important. Roughly 10% safety margin is advised but more is better.
Regards Amps then what's more important than safety margin is being able to select the correct motor amps. Most drives only give you few options on current selection and usually there's never one exactly same as motor rating. In this case it's best to select next lowest. However the AM882 allow you to set (via software) current in 0.1a increments so can get exactly right.

Won't go wrong with AM882