Not sure, my incubator is smaller. I just set it up and put in as many as I can. At the moment I have 6 duck eggs that are due to pip this week. I always leave a small gap between the eggs. The only issue I have had with space is when they hatch. They usually take a couple of days for all to hatch and needing to leave the tiddlers in the incubator to dry out with unhatched eggs mean space is tight! It usually works out ok.

If you google the make you should find the number it can take. This is never precise though I think as eggs vary in size. Hope you have success.