As mentioned in another threat, I use this one:

this one would be perfect if it had a helmet mount. 350 lumens, 70 grams.
https://cygolite.com/product/dart-pro-350-usb/



It is the perfect commuter light for me as it is so, so low profile and unobtrusive on the handle bars. Easy and Light enough to be mounted on my helmet too. I use it all year, day or night when commuting.

It is so low profile and integrated, it looks like the bike was built for that in mind.

I tend to mount other commuting tools on the stem (computer) or just below the handle bars (bell).