LOL Ian
May I suggest if you have the time to write a summary of the conclusions you have come to so far. From my understanding of steppers it is the voltage that determines the speed and the current that determines the torque and I suppose most importantly the way the motors are driven has no relation to V=IR, is this correct?
I am dealing with AC Servos at the moment and from my understanding they have a constant for Torque/Amps and Voltage/RPM and the drive is able to supply the current and voltage independant of each other, this means that I can get max torque no matter what RPM the motor is turning. Obviously it is different from steppers but the principle of voltage and current being independat of each other seems to be similar, and the relation of Voltage to RPM and Current to Torque seems to be similar.
Maybe my understanding of both steppers and servos is totally wrong so I have already donned my hard hat and have taken cover
Hood