ok, so if sourcing bigger fish isnt an option, then maybe along the same lines of what your thinking....maybe consider stocking the small ones 5" which should be available and raising them in the pond like your doing, but when you catch them in the 11-13 inch range put them in the cage and feed them a steady diet of minnows and bluegills to beef em up for a few months and then let em go.... I think if you can get em over the hump and into the next size class of forage availabity that they will flourish just like the ones you put in advanced sized...
plus believe it or not, once you get them trained in the cage to eat your injured bluegill offerings, then you will be able to keep them on your injured bluegill offerings right off your dock!! I cant get the walleye to eat directly out of my hand, but I can get them to eat injured bluegill I toss out in the water!!
Same with crappie, they too will eat pretty big bluegill injured from the dock....the only problem I can see though that will hamper your training your fish to eat is that the dock is also your favorite place to fish....
At my place the dock that we train the fish to eat from our hands we dont allow any fishing...the fish have picked up on that for sure and the biggest fish in the whole lake live at that dock and are very happy to see people coming out onto it!
I can always tell though when someone has been fishing (poaching) from that dock because it takes the fish a couple days to become friendly/brave again right out in the open...
so basically what Im saying is when we come to Nebraska this spring we are gonna need to build ya another dock....
