Sounds like your hatch is going well even though you have not monitored the humidity which is good, the room where you are incubating must have had an acceptable level, I don't believe it is as exact a science as some would have you believe. I got a cheap stick up hygrometer from a pet store, one that would be used in a lizard terrarium, it is off a few points when I checked it but not enough to worry about.
I have a batch going right now and I personally don't think adding water is necessary, I have a styrofoam incubator that holds 42eggs in a turner and it seems the moisture from within the eggs is holding the humidity plenty high, it even gets up a little higher than I like so I will remove an extra vent plug for awhile to get it back down. At lockdown it is recommended to boost the humidity up over 60% some say even higher, this is to keep the membrane beneath the shell from drying out once the chick pips as the membrane can become tough for them to zip open. Judging from what is happening with the humidity levels in my incubator i think the humidity will spike on its own once the eggs start to open and wet chicks come out.