--- Begin quote from "mswhat"
If you're finding 8-11" ones then you hit the gold mine!
--- End quote
When I used to go fishing, there were two different "kinds" of blue gill. One was lighter tan colored and would quite often get nicely sized for filleting (consistently longer than my hand). The other were darker, more greenish color, and they were typically smaller but thicker. At the ponds where we caught those, ones big enough to filet were quite rare. Most places had one kind or the other. I am not sure if they were different species, variations, or just different growth phases of the same exact thing.