IMHO you've really gotten advice that is spot on so far.
Determine if you have small BG by fishing with micro stuff. Try all kinds of feeding techniques, locations, and foods, all the while observing closely.
If you do add fish-BG, HBG, etc., try to get larger fish, bigger than what your two main predators can eat. Consider overfeeding your pond just before you release the new fish so that those predators have full bellies. Perhaps you'd want to cage your new fish for a couple of days. If you can afford it, dump several pounds of FHMs concurrent with the BG stocking to take the pressure and interest off the new sunfish.
3 years ago I added BG to our 1/4 acre bass overloaded pond. 2 years ago I added GSF. When I added BG I started pounding the LMB, removing more than 100 that first year. Next 2 years I killed another 75 or so LMB. So far this year I've only caught 7 of those dastardly "green trout" (bass) and only see a few when I'm fishing or walking the pond banks.
The YP and GSF numbers in the pond are rapidly increasing. Yay! The BG not so much. I saw 4 or 5 larger (7" to 9") BG yesterday while fishing, but not a single smaller one. The smaller BG must be getting eaten much more readily than the GSF and YP. Mine is a cooler water pond; trout persist over the summer. It could be that BG recruitment will not equal or exceed that of GSF or YP due to cool water temps.
Can any of our sunfish experts offer insight on what's keeping the BG numbers so very low and allowing the GSF and YP to apparently prosper? I still have a few oversized LMB, greater than 20", in the pond, that will never see water again if I can just get them flopping on the bank.
