I'm in the same boat as you Ernie with needing to keep the humidity lower even this far north for the first 18 days. Nothing more depressing than when you are really excited about a hatch and open the eggs only to find that they were perfectly formed, just drowned.I can't tell someone else how to run the incubators or hatchers, but we cannot get anything to hatch with the humidity that high. We run our incubator at about 30-35% humidity and hatch at about 60%. We have to run our incubators and hatchers on lower humidity to get our eggs to evaporate correctly. We drown too many chicks if we try to run a higher humidity. Hopefully, someone else will chime in later. I know that there are other breeders in this group who are very successful at hatching Marans chicks.
Just My Experiences,
Ernie Haire