if you use normal eggs, when you turn off the air pump for the hatchery, all the cysts float to the top and the baby brine shrimp sink to the bottom. I found i'd suck up a few cysts, but there was nothing I could do, not like you can pick through and seperate them out though.
Search caudata for an article called "micro-foods" it has a great photo of a 2lt plastic bottle hatchery set up, which I based my milk bottle hatcheries on. From memory the recipe is, 2lt water, 1 tspn salt, 1/2 tspn cysts.
You will most likely need 2 or 3 hatcheries going at once staggered a day apart so you have food ready for daily or twice daily feedings.