Well, I have 40 jars in operation, and about another 30 sitting empty until I can get more fiberglass mesh for covers. I like the fiberglass mesh (ie: bugscreen) because it is flexible yet rigid enough to work with and allows air but no hairs and other floaties into the jars.
The males have grow considerably faster in the jars, and are acting like males now, flaring at each other, growing longer fins, ect... while the males left in the grow-out tanks are still pretty small.
I am cleaning the jars each week, by shiphoning each jar with a small tube (1/4" dia. line) to clean the bottoms, changing about 80% of the water each time, then putting a pail of fresh water on top if my shelving, and siphoning the water back into each jar from the top. It works pretty good, I just use my fingers to stop the siphon line flow in between jars and I can move along pretty quick. About 40 minutes to do 40 jars, including getting a couple pails of water from upstairs.
I am feeding them twice a day, staple flake food in the morning and frozen brine shrimp at night. I crush the flake and thaw the shimp cubes, then use one of those childrens medicine dispenser/needle-like things from my drug store clerk (free) and added a like airlline tubing to hold the water/shrip so I can put a drop in each jar through the small hole in the fiberglass mesh covers.
I am likely a month or so away from selling them yet, but so far I still have around 236 young adults in total, and I am managing to keep up so far.