How quickly do CNBG grow if being fed AquaMax MVP.

Also, is it possible to cage grow 3-5” BG? I can put the cage directly beneath the feeder.

I'm no help on CNBG growth, but I keep a few BG females in a holding pen and hand feed AM500 to them. It's one way I try to manage my spawn rates. Every female I catch goes in there. Probably not near as many individuals as you're thinking, but the few I have seem to be doing fine. I'll let them grow until they get big enough to dance with some hot grease.

I was thinking I could build a 5x5x5 cage to put 3-5 inch BGs in so they could grow through the summer. The larger ones I could probably release very soon, the smaller ones I would want to grow a bit longer.

I may could even set the BSF feeder to drop in as well

Mine is a round 4' diameter by 4' deep. Frame built from 1/2" pex and enclosed w/ 3/4" nylon fencing. Minnows can easily swim in so the BG have feeding options. Free floating with pool noodle on the top rim and allowed to drift. I have it tied off on the dock.

I wouldn't have an issue keeping a couple dozen fish in it over an extended period.

i have a cage about 4x4 that i am currently raising cnbg in. i bought 200 in early spring at 3-4". i lost about 25 or so within the first week or 2. the rest are doing awesome. i hand feed them aquamax 300 several times a day. i feed them 5 or 6 times a day if i am around the house, but almost always twice a day. i feed them until they won't take anymore each time.i am trying to get them to as close to 6 inches as possible to keep bass from eating them upon release.
i have posted some pics on here before of bluegill they take up in the cage. if you throw feed in your empty cage the bg will come to eat and eventually stay until they are too large to get back out of the cage. i have done it several times.

In the south BG grow very quickly. They can in good water with quality feed grow to 8 inches in under a year. From 2 inches in early spring to 5 inches in late summer/fall should be easy to accomplish.

Do y’all put a lid on your baskets to keep birds out

I'm sure you'll want to at the least build a mesh cover with some sort of frame. You might be surprised at the critters and how they figure out it's a concentrated source of food.

I had some perch in a cage for catfish river bait purposes, and had a big problem with small to medium sized snakes sliding in and gorging themselves on fish to the point of not being able to get back out through the mesh.