Where will I find "motor curves" thats a new term to me.
The seller may have them for the motor. Most name brand motors have motor curves and usualy they are done for 24 or 36 volts along with
the different winding configurations. As a prep on your learning curve you may want to have a look at the first few threads of this link which is
about a lathe retrofit i did.
http://www.machsupport.com/forum/index.php/topic,12484.msg80823.html#msg80823Then go to the Gecko Drive site and read all the info that they have posted. Then maybe read Jones on Steppers, if you want to get into more detail,
and you will have a good understanding of the power supply, drive and machine relationships.
So it seems what goes in from the power supply via the board gives you more power at the motor
Not quite right in the big picture. If you were to design a cnc system you would define the machine application, then select a proper machine,
then analyze what the axis needs to do along with the machines physical aspects and after some rationalization select the approriate motors
and power supply to do the task. Computer may also come into play in all of this. Once you have determined what is required and selected the
item off the shelf you then pay the price...or...... go back to the beginning of the design and make comprimises.
You are ask backwards in the approach, let not your heart be troubled, since most of us do the same thing and the saying "doing it right the first
time is echoed".
RICH