Arrgghh!! I knew I forgot something!
The tower should be 34.5 mm tall, and the lip should be 1.1mm wide. Aluminum would be perfect. I'm planning on using XR-E R2s, Cree UV and/or the Cutter triple XPE setup.
I wanted a thick tower to make good thermal contact with the metal head of the W200.
Pack, on your cut-down stock heatsink, how did you put a driver/board in the top? I saw Johan's thread (you two have got me going off on U/W lights, now), but I couldn't make out his cut-down process.