I took the potentiometer Diachi gave me, and the 25 pin connector and just hooked it up too that in the right place, as well as two 6mm connectors to plug my DMM in.
Yeah exactly. The max current the PSU can source for the controller is 20mA for the -ve and +ve supplies. But you wont even get that draw through one potentiometer or resistor. Probably around 5mA tops.