I can't help you with all your questions, but just wanted to add for others looking for something different, peterwhitecycles website has photos of light beams from various German lights. You can also find some on the Busch & Muller website. I think it was bumm.de if I remember correctly. If you check amazon.com you'll find some wheels with dynamo hubs. I'm hot and horny for dynamo hubs. I want to build a light touring bike with a dynamo hub and it will likely be built with a Deore LX dynamo hub.

From what I read (forgot where), the light beam for lights in Germany are supposed to cut off at some point to aviod blinding drivers. I know Harriscyclery.com has some german dynamo lights. I'm contemplating getting the Busch & Muller Lumotec Lyt with 25 lux partly because it's less expensive.