OK, I will play with rules and let you know.
WIth 1TRIGGERS_NIGHT_MODE=true in Bridge definition, right? Yes thats cool!
With original Mililght Binding i did it with loop and increase or desce dimmer by steps (5-10) with 400ms delay in between. But not always go smooth, as opehab delay sending sometimes or bulbs not get some commands - basically it was too fast for the path to each bulb. And the main problem was, bulbs always remember last dimmer state and i was not able change it. So turning on always start with 100%flash. The rule is in this post.