Gecko 210 power supply ?

I am in the process of building a power supply for my cnc router,
Going to use Gecko 210 (3off).
I am driving 3 off stepper motors 2.8v @ 4A/phase
would i use a 45v transformer (45v*1.4=63v) or a 50v tansformer
(50v*1.4=70v) the latter being exactly 25*motor rated voltage.Both
are 1KVA.
The motors in question are sanyo denki bi-polar motors (103h8222-
5141) rated at 5NM torque.
I was going for the 50v tranformer but am i too close to the limit
of the gecko or motor
any advice would be appreciated.

Regards
Mark Tucker