I fill my water tray when I set them in auto turner
I candle around day 10 or 12 refill water tray
I candle and take out of turner day 24 refill water tray and leave them alone
I have never measured my humidity so I do not know what it is
I read somewhere you should mist duck eggs and the one time I tried that I had miserable hatch rate so I have never done it again.
One thing that threw me for loop when I first started hatching duck eggs is they pip then make a hole in egg and work on that hole to zip and sometimes it can take 2-3 days!!