Quick update just in case anyone uses Leadshine servos in the future. Hook up is pretty simple, you just need a pot 0-5VDC to set the speed (configure the speed input to be 0VDC => 0RPM and 5VDC => 3000RPM), 12VDC and some transistors (or the mentioned ULN2003 array) to drive the enable input on the servo controller. I'm using a PIC to toggle the enable transistor and the servo runs of a 13A plug, via an AC filter.

Regards,
dsc.