Ah, the million dollar question.
A coworker friend of mine breeds corns/bulls/grey-banded kings and I brought the eggs initially laid to him to look at. Of the original 17, 6 were potentially fertile but we didn't have a flashlight on hand to candle them. Of the 10 she held on to, 5 were really juicy to aspirate, the rest were slugs.

If things had turned out differently, I might have had a whole pile of little pink clones on my hands!