As jason said, if the female holds the eggs past the first week, you're generally good to go. Unless there's a huge change in your tank they will generally release young after that first week.
So if you wanted to move females, it won't matter what size clutch they have. However, for research purposes you'd want females with more eggs so you get more data, and decrease the randomness. Move a female over, if she drops eggs then move her back and wait a month. If she keeps them past the first week you should have babies.