The high humidity probably won’t make any significant difference. Instantaneous humidity is not what’s important, it’s average humidity over the entire incubation period. Just run it a few percent low after your hatch for a few days to compensate.
Of more concern to me is that you are supposed to turn eggs when incubation starts. Turning is more important in early incubation than later, after two weeks turning is not important. How do you plan to turn them? If it’s with an automatic turner those pose a danger to the hatching chicks. They can get tangled up in them and injured.
Also, when chicks hatch they make a mess. They trail slimy goop after themselves as they crawl around plus they poop. They can make a mess on your eggs that can lead to them getting bacteria inside, which not only kills the embryo but can cause them to leak a foul fluid or even explode. You’ll need to clean your incubator well after the hatch anyway because of the poop and mess. Otherwise the entire incubator will really stink after a few days.
I don’t know what your incubator looks like but isolating the hatching chicks might be a really good idea. I can think of two possible ways to do that. Make a basket out of hardware cloth or something similar or use some kind of mesh basket, and set that over the early hatching eggs. Some people use plastic mesh baskets that fruit comes in. That isolates the filth. Or maybe you can build a fence across your incubator, again hardware cloth works well but use your imagination, to keep the early and late eggs separated.
Good luck with both hatches.
