Well, the PT Eos mod is done. I used a LXHL-MD1D Luxeon Star, and the net result is quite bright, around 800/300/65 lux at 1m as measured by my EA30. As a comparison on low, that is about 10% brighter than my Jet-1 MK. IBS, although it looks visually at least 50% brighter so that may come down to meter accuracy with 625nm light. I need a lower low for astronomy, so I'll probably see what can be done with the regulator, to see if I can get this down to 80/30/6 or so.
The LED I used is rated at 44 lumens/1.1W, so some of those Cree XR red LEDs rated at twice the current would be very intense if driven at capacity, assuming your headlamp could dissipate the heat.