I know this is a little late, but I finished a Bridgeport Series 1 CNC conversion a bit ago.... I used the Gecko 203v drivers with great success. Set to 7 amp output. 72VDC @ 20amp power supply. The motors do get somewhat warm despite the heatsinks. I have reliable 120 IPM rapids. (and to clarify, I've never tried any faster. I'm happy with 120 IPM, and I don't have the free time to play around). The machine is in a production environment...Used 7 days a week, all day. For the heatsinks for the drives, I cut down some of the original control's heatsink and machined it flat for the drives to mount on. I really believe that calling the Gecko drives "hobbyist" is far off base with reality.