Welcome to the fish hauling world!

I cannot advise you on how much fish to haul using a bubbler as I use pure O2 to haul fish. AND I monitor the O2 levels in the tanks with an O2 meter. (YSI ODO Pro) I check O2 levels 15 minutes after loading the fish, 1/2 hr after loading the fish, then if it seems to be stable, every hour after that and adjust the flow rate on every tank individually using flow control meters. Air has 21% O2, so a person can't haul near as many fish per gallon of water as a person that uses 100% O2. Plus you have Nitrogen from the air going into the water too.............

Using pure O2 I run roughly 1/2 pound of fish per gallon of water. How big were the CNBG? I can calculate their weight if I knew that.

Also, a pound of 2" fish will use more O2 than a single fish that weighs a pound.

Who did you go to to get the minnows?