Samualt,
I wouldn't get too distracted by the big numbers of max peak torque and peak current. Those are design limit parameters, not optimum running conditions.
The motors will stand 9 amps continuous at 60 volts, so that is what you need, plus a little reserve. If the power supply has a capacitor or two, it may give you the capacity for the peak surges, which are only momentary conditions.
First you get good, then you get fast. Then grouchiness sets in.
(Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)