I just want to share how to position the Lupine lights differently - at the fork crown using the helmet mount. Main benefit is that it's lower to the ground so that you get much better terrain reading, because of stronger shadows. And I don't recall any drawbacks. You can use old or new Lupine helmet mounts, as you can see in the photos.
I have been using this type of mounting for years now. It is very simple method, mounted in seconds, very sturdy, light is out of the way and completely centered. For me it has become my standard mounting position. I use Piko on the helmet as the second light for more challenging rides as well.