Papa, have you checked out the hatching 101 section in the learning forum here on BYC?
I agree with others. I incubate at 35% and lockdown around 55-60%. I've also read from some 'experts' to leave the air plugs in for the first 10 days and then remove them.
I never put any plugs in or close any vents. The first thing I do on styro bators is throw away the vent caps. All vents on my cabinet are always completely open.