I use this on the handlebars:

https://es.aliexpress.com/item/32679...chweb201603_55

And this on the helmet:

https://es.aliexpress.com/item/32614...chweb201603_55

Note: I have no affiliation with this seller. It's just a link with the same product I bought.

The first one has a nice spread and more than enough power to descend at hight speed. I power it with a 6 cell 18050 battery attached to the handlebar. Battery life is around 3hr at low setting, and 1.5hr at max.

The second one has a more concentrated lightning area. Not ideal for great forward vision as it lacks enough spread, but excellent to light the area that I'm looking at. I power this with a 4 cell 18050 battery I carry on my backpack. Battery life is around 4hr at low, and 2hr at max.

The helmet light comes handy to look the sides of the road/path for wildlife and other potential hazards. Also, it lets me see around me and not just in front, which is always nice when pitch dark, and finally, provides a backup light in case the other one suddenly fails, which is something I always worried about when descending at night.

If it's a lighted area, I only use the handlebar light at low. On dark areas, when climbing, I use both at low. And when descending both at high setting.