Grrrrr....had this really nice post all written up then hit the refresh button and poof, it's gone. Here's the gist:
KTR bike choice: the route screams for 29" wheels after Magpie hill. I ain't deaf; the Dos is in.
DIY LEDs: the second prototype is ready for action. Here's pics.
The housing is aluminum pipe stock, 5W Luxeon Star LED, powered by 700ma buckpuck with pot & 8 AAs. Should run about 4.5 hours at high, lot's more with judicious use of the pot. Mount and connector wires poached from an old niterider setup. It's not heavy - the light is 54g, total system about 280g, all on the helmet, and bright too. With NX05 optics there is no dreaded dark spot in the center of the beam pattern.