Duh, just thought of it. Are you using a auto turner? You could take the turner out and only roll the eggs that need to be. Hard to work with humidity but we have run all our chicks as dry incubate. When ours go to the hatcher/brooder is the only time they get some extra humidity and we don't even monitor it. I built the hatcher myself and it just has a can of water next to the light bulb. Nothing scientific but we get 90% to 100% hatch rates.