Just thought I would mention what I did when I had a staggered hatch like yours. One day I went over to a ladies house to get some duck eggs and she ask if I would like some other eggs as well. I said sure. She had several silkies sitting on the eggs and they were in different levels of development. So I took them home and set them in the incubator with an automatic turner. I never did check the humidity (don't have anything to check it with right now) so I just put a plastic container of water in it. After that I just left them alone (except to candle every now and then to see if anyone quit). I left them in the turners and never did anything different with the humidity. All but one that didn't quit early hatch out all by themselves. 1 died at about day 18. And another I did help but I think it would have made it on it's own if I hadn't messed with it to begin with.