Got to work lighting up the eyes. The LEDs are rated at 3 Watts each (silly bright) and the driver board is a Sparkfun FemtoBuck. The FemtoBuck is a constant current LED driver board that can accept a PWM signal to dim the LEDs. Wired up the eyes and holy crap are they bright. They're perfect.
Next I made a clear sheet plastic lens, scuffed it with a scotchbrite pad and added some polyfill behind the lens to help diffuse the light and then I placed the lens behind the iris. So far I'm pretty happy with how it looks. The pics show the full range of iris motion.