I am afraid I don't know anything about the motors.
as for using a resistor, we found that is not going to do anything.
The fan is either on full or off by direct power.
The controler I linked will help control fan speed. It has multiple settings based on engine temp.

If you don't want a controler, then on or off are the two choices if you get the correct fan.
The other type won't run long without the controler.

if feets doesn't show soon to post the pics of the two fan types I will try to at least get a pic of the fans that can run without the controler.