Here is a "don't worry about it so much" story:
Once I ordered 6+ of shipped eggs... bantams... two strikes against a good hatch already from the word "go"
I set them... used a digital thermometer that read 100F... so I was happy. I went to bed then work (ten hour shifts PLUS drive time)... came come in the evening. Noticed 112F!!! That is not a typo One Hundered And Twelve!!!
I took the lid off for about 3-5 minutes, went and got two other thermometers, cleaned them (outside porch style), put them in... yup 112F...
Off the lid came again, turned the dial down three whole turns. Placed the lid back... 102F... turned another half turn.... 100F.
Some would have gave up and threw the eggs out.... I went the distance with them and got (drumroll please) 100% hatch.
Don't stress so much. You'd be amazed what they will hatch through. (I know a friend who lost power for DAYS and still got some to hatch - dead of a snowy winter)