Your problem comes when it's time for the first batch to hatch. You should stop turning, raise humidity, and not open the bator from day 18 until after hatch or you risk killing the ones that are hatching. During that time what happens to your other set of eggs? The higher humidity will keep them from losing the moisture they need to for possibly 4 or 5days and they won't get turned unless you leave a turner running which has risks for the ones hatching. No matter what you do you're likely to get a lower hatch rate from one set of eggs or the other. That's why people keep a 2nd incubator running as a hatcher when they do staggered hatches. Then you can have 1 incubator running hatching conditions and one running incubating conditions and just move the eggs when they reach day 18.