Lots of good suggestions. The light from Fastec looks good. I use a $25 LED flashlight with single 18650 LiOn battery, mounted with an inline LockBlock rubber/velcrow chineese knockoff thingie (forgot the name) on top of my stem instead of on the bars. Carry a spare loaded flashlight (my son's) and one spare battery because I'm paranoid. Also a low-power 80 lumen (stated) 3-AA headlamp on my helmet for close, handy lighting. Like if I have to stop on the ride for something.
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Disclaimer: 99% of what I know about cycling I learned on BF. That would make, ummm, 1% experience. And a lot of posts.