My goals with humidity is to keep it as close to outside humidity as possible.
Let say it is 40° F outside with humidity of 50%. If my readings inside are 60% or more I make sure to remove water dishes from the coop, clean up any poo and open another vent if I have any closed.
If it is more than 75% inside while 50% or lower outside I do a full bedding change in addition to opening all the vents.
Something to remember is if it is you wont be able to get lower humidity inside then what it is outside.
It helps knowing in winter to manage moisture to prevent frostbite.
I wanted to use some suntuff on my coop. I also wanted my metal roof. The two wouldnt mesh correctly so I did full metal but made a bunch of windows.
I like a bright coop as well.