I think there are a few experienced dry incubation people here, but for the life of me I can't remember who. (Early morning brain fog.)
Since this was my first hatch I didn't have the courage to do a dry hatch. I kept my humidity around 45% until day 18, and then cranked it up to 65% during lockdown. My eggs were mail order, so I was already concerned about how many would survive shipping. I ended with a 69% hatch rate, which I was happy with for my first experience.
I did read one comment recently on one of the threads that made total sense to me....When the momma chicken sits on the eggs, she doesn't make adjustments for humidity and still manages to hatch her eggs. Now, I know that moisture from her body creates a more humid micro-environment around the eggs, but I sincerely doubt that anyone in AZ has bothered to measure that level.
If you haven't already checked it out, here's a link to dry incubation that I found very helpful:
https://www.backyardchickens.com/a/hatching-eggs-101