I ended up using the FlexMod P3 for my driver...It did everything I wanted and had plenty of current range as well. My "lab" supply is now alive and running. I had a slight problem with my TTL oscillator on first power up. Got a replacement capacitor today and will install tonight. This has been a fun project so far. Particularly after lighting my first diode ! ! ! I might start another thread as a place to keep track of everything.