No worries, I usually lockdown at day 16 or 17 (but don't raise humidity until day 18), I feel it gives them more time to get into position (just my personal opinion). I honestly don't think there is a "one size fits all" for incubating. I did everything the way the manual told me the first...
If you set them Saturday morning Sunday morning would be day 1. You never know how hatches are going to go, I've done 2 hatches this year and both were 2 days early, my broody hatch was 1 day early. Last year, besides the occasional early bird they were all pretty much on time.
Just wad up some tissue, paper towel, toilet paper, whatever, and dip it in there to suck out some of the water. You will have to give it some time for the humidity to adjust afterwards.
It'll be less stressful the next time, lol. I actually took off work for my first hatch and got nothing done for 2 days because I was staring at thermometers and eggs🤣 Trust the govees, and try and relax and watch the magic happen.
I have the same govees and some older versions, they are pretty accurate. My NR360 was spot on the first year I used it, but this year it was off by almost 2 degrees (I always run it for a few days empty with a couple govees) I adjusted it accordingly. Do keep in mind that as the NR360 rotates...