I don't go with a helmet mounted flashlight, but the same question could be asked of my minimal setup so I'll answer too.

I typically finish riding for the day fairly early and turn in for the night at or a little before dark. So I rarely read in the tent after dark. In fact on most tours I don't read much at all, but when I do it is most often by listening to audio books. I have sometimes taken a paper book or a kindle, but typically read while it is still light when I do.

For cooking, I find a 5 second peek once in a while to be sure I am not scorching dinner is sufficient. That said more often than not I cook and eat dinner before dark. I do eat first breakfast in the dark, but it is pretty often just a granola bar or instant oatmeal.