It's funny ... i grew up in a time when specialized information was relatively hard to come by, and trying to find a way to mount a light on a bike was more an exercise in creativity than a matter of research.
Now i have almost all of the knowledge of the human race throughout history readily available .... and very easily searchable.
And somehow, some people seem not to live in this world.
Seven out of ten posts here could be completely answered with two words: "Google it."
And, no joke, I said that to someone once and the replay was, "I don't use Google, it doesn't give good results." The person was not able to understand that "Google it" actually translates to "Search the web."
I guess she should have googled it.
Hope the OP has successfully mounted the light.
Those old-school aluminum bottle-cage mounts (as shown in post #29) work wonders in all kinds of situations.