I use my bicycle for commuting, mostly over the secondary roads closed for the majority (not all) car traffic. There are other cyclists, dog walkers and runners on these roads.
Using the light often, I would like to find some grounded answer, how they should be used in the most safest way. When I start do dig deeper, multiple solutions appear and the things start contradicting each other. Looks like there the following strategies are generally possible:
Rotate your (StVZO certified) headlight into the ground ten meters in front of you, all done and ignore complains from bystanders about the intensity. The major concern here is, unlike a car driver, I frequently encounter random people standing on my road. I am afraid not to see them in time if I only illuminate the road and they shoes. I was ten minutes from buying Supernova AirStream 2 but ran into this #2 Google hit negative review.
Rotate your (StVZO certified) headlight into the ground ten meters in front of you and reduce the intensity till everyone is happy. So we have done everything not to disturb the other traffic but this may not be fully adequate for spotting some black dressed runner carrying not even passive reflector.
Buy dual beam light so you can switch off the high beam when you see other traffic. The main danger here is, the object may disappear after switching the beam, as once happened to me when I ad hoc shifted the light by hand (there was also a light fog). Also, people not carrying they own lights or at least reflectors, can be spotted in time to avoid them but not early enough to adjust the beam (and some later yell).
Use wide and high beam and adjust how it is better for you. Simply reduce intensity until nobody complains (that is possible to achieve) and then move on with the speed still good enough for your light that now melds nicely with twilight. This technique is described in this document as "Weak headlights with wide diffuse beam technology". So far this was my compromise between the "peace with community" and "perceived safety". Is it really so bad, has any serious analysis ever been done about this approach?
Use narrow beam. I found it unsafe in turns, basically turning into darkness. While not encountered, I also think that people may wander into the beam (and path of your bicycle) from the side much closer than this nice far view.
The ideal answer would provide some statistical safety comparison or at least in depth analytical comparison. Surely any lamp manufacturer claims they product is the best. I wonder if any more serious analysis has ever been done. The country where I am does not have very specific or strict light requirements beyond the sane mind.