I'm night weaning with a gro clock just like I did with my eldest. Moon means no milk, sun means milk allowed. First night will be changed from moon to sun a very short time after waking. I've positioned it so I can do this surreptitiously. The first night is to show her it DOES change. And to cement the rules of the clock. We've done practice runs lots through the day today. If all goes to plan then tomorrow it'll be longer before I change it to sun.
This method worked really well with eldest. Let's see how this one goes!