You will be surprised that you're current readings will be wrong once eggs are in. The eggs will reduce the air volume in the machine. This means the humidity will go up once eggs are in the machine. It was still a good idea to run the machine to check the temp, but that is it. Just fill the one cavity, but in eggs and see where the reading is a couple hours later. Don't worry it will not hurt your eggs. I once forgot to add water and it went down to 20 per a whole day around day 14. They still hatched fine.
Katharina
Katharina