During the night the screen is still too bright, so I added the gamma option, like this:
wlsunset -l 1 -L 1 -g 0.5, which looks very nice.
Only to notice that that gamma is also applied during the daytime. Of course, I can set the low temperature too, so this is not a bit problem, I thought it worth mentioning.
wlsunset does not currently have features intended for brightness reduction, only blue light filtering.
Support for running a script on change that could be used for setting brightness has been requested often, I just never got around to it.