SO, I got a couple of these 80w DC - DC buck converters to supply power to Houston. One is going to be the 5 volt supply for the servos, the other is going to be a 7.2 volt supply for the Rover 5. Last night I got a motor out and adjusted them to the proper voltages.
The thing that's got me confused is the "constant current" part. There are two multiturn pot type adjustments. When I ran the motor, it pulled about 350ma turning the current pot didn't seem to change anything.