Yes, the size of the eggs would affect the moistness.......and so would the light eggnog.
Should note that the “slightly dry” comment (for the second batch with light eggnog and large eggs) came from a woman with quite a baking background...Her mom did a TV show on cooking/baking, and her son went to culinary school and is now working at one of Chicago top restaurants...tough crowd for my first foray into this ;)
Well, I will make notes and be sure to use regular eggnot and I think I will go with the medium eggs too :)
Tough audience for your endeavor.