I now have dedicated broody hens but when I incubated ( only hatching from Feb to end of April) I did not put any water in my Styrofoam incubators and with the relative humidity here in Louisiana this time of year it was usually still too high. Around upper 20's to low 30's would be optimal till lock downThis is good to know as I had my own bizarre hatch experience with this one and had to have the humidity on the high side for a while. I will be vigilant during hatch.
Make sure to look up the guide to assisted hatching on this site! Read it in full and TAKE YOUR TIME!!