If you haven't found this before it gives very detailed instructions of the experiment in Japan.
https://www.jstage.jst.go.jp/article/jpsa/51/3/51_0130043/_pdf
They wiped down the eggs with 70% ethanol before cracking them, which is something you could do before you open yours, and they kept the humidity at 80% for the duration of incubation.
This is fantastic!!! I had searched for a thorough guide to what was done. This is the best I've seen! Thank you for sharing!