Graham, it sounds like you have several areas of concern. To support a bass predator population that size, you need thousands of CNBG, not hundreds.
The clear water indicates a lack of phytoplankton base. Phyto is the base of the aquatic food chain and without it, nothing much works above it. Phyto, Zooplankton and the tiny bugs that live on them are what the fry live on. Pretty, clear water is not a good deal to fish. I would suspect that you need to fertilize but first you need to check the water quality. Go to the Texas A & M website and get the directions for obtaining and sending a sample. You should get written results and recommendations within a couple of weeks. BTW, I almost never recommend fertilizing in this area. We seldom need it. You obviously do.
Back to the CNBG. It takes 10 lbs of forage fish for a bass to gain one pound. If you are bass heavy and forage light, the chances of larger bass is almost nil. I'm pretty sure that this is your situation. Too many hogs at the trough and you're loving the hogs to death.
The remedies as I see them at this time:
1. Get the A & M water test. It's pretty cheap. When you get it, take the proper remedial action.
2. Forget about catch and release on the bass. That may be a good idea on heavily fished public lakes but it can be the death of a pond. Start cleaning out the small bass. Eat them, toss them, relocate them or whatever. When you have taken out just about all of the 12 inch or smaller bass that you can stand, take out that many more. You won't hurt the population.
3. After fixing the water and clobbering the bass, stock 750 to 1,000 four to six inch CNBG and about 100 redears. By the time that you stock them, you should be catching bigger average size bass. If you work at fishing, you should probably figure on being able to stock the forage by next Spring. I would also consider stocking about 10 lbs. of tilapia to help with the moss and vegetation problem. They are also prolific spawners and should take some of the pressure off the CNBG so they can get established.
BTW, an awful lot of us have made the same mess out of our first water hole that you have. My first one was a lot worse. So, take heart. This is fixable. All it takes is fishing hard and $. At least, there are 4 of you to share the pain.
Anybody have any better ideas?