Looking at the datasheet the M6R5 has two notations Rs on the center taps tied to pos supply lead and polarized capacitor between pos and neg supply leads. Iím thinking the R is resistor the s maybe dependent on the either the motor or voltage input? And the same for the capicitor? If true, what would I need for 12dcv/1.2 phase motor?
The capacitor should probably be at least 470uf and at least double your power supply voltage rating.
It doesn't say what the voltage rating on the drives is, but with 12 volt motors, you will need all the voltage you can get. You generally want a power supply 8 to 10 times the rated voltage of the steppers.
If you don't aready have the drives and steppers, you would be better off looking for different drives and motors. You want motors under 5 volts, and the lower the better. If you know how to solder, you can get a modern 3-axis drive kit for less than the price of 3 of those ancient drives. http://www.hobbycnc.com/driverboards/4aupc/4aupc.htm