If big bluegill are your priority, skip the crappie - they get too big for bluegill to eat very quickly, and beyond that they'll compete directly with bluegill for food and thus lessen the size of the bluegill significantly.

You don't have to go with hybrid bluegill to get them very large; numerous studies have found that regular northern-strain bluegill grow as large or larger in the long run on pellet food than HBG. HBG will get bigger on average in a pond that isn't fed, especially if there are a lot of FHM, and they grow faster initially regardless of the circumstances; but the state record bluegill for IL was three and a half pounds, and it was a common northern-strain bluegill. Bruce Condello on here has caught more than one northern-strain bluegill (though I should note he has his own sub-strain that he's been breeding for ten years) over two pounds. And the huge advantage of northern-strain over HBG is that the HBG are only good genetically the initial, stocking generation; they denegerate greatly even in the first generation of offspring. So you would have to re-stock them regularly. Whereas northern-strain bluegill do not degenerate genetically at all, and once you've created ideal conditions for them in your pond, all you have to do is maintain said conditions and the bluegill will get huge year in and year out with no re-stocking.

I would recommend you look into getting some of Bruce's 'gills. He's moving to a new spread, so I don't know the status of his bluegill, but if you could get some they'd be worth their weight in gold. Another possibility is the Jim Frey hatchery in West Union, IA; they specialize in large northern-strain bluegill and have been breeding them selectively for years, and they deliver to IL:

http://www.jimfreyfishhatchery.com/consulting.htm

Another note: I would recommend against HSB if big bluegill are the number one priority. HSB are a great fish, with lots of fans on here, as they get huge in ponds; but part of how they get huge is by being fond of pellet food, which means they'll directly compete with the bluegill for it. Big channel catfish will literally knock bluegill out of the way with their tails to keep the bluegill from the food; unless HSB are atypically generous among fish species, I'm guessing they would do much the same thing. At a minimum, they'll eat a lot of the food that would otherwise go to the bluegill if no other species were present that ate pellet food. So I would suggest, as someone who specializes in big bluegill, that you not stock any other species that eats pellet food: no CC, no HSB, and no grass carp (which most definitely will bully bluegill, and eat enormous amounts of pellet food).

My recommendation would be to stock 300 bluegill per acre (this number is significantly lower than those normally recommended by hatcheries, but will result in faster growth for the bluegill) if stocking fingerlings, or 150 if stocking fish 3" or larger; 100 largemouth per acre at least, perhaps 150 if stocking fingerlings; 50 redear per acre; and as many FHM as you can afford (you can't have too many of them, and the more you stock the better chance they have of establishing). You might also consider stocking grass shrimp, which are a favorite food of bluegill; TJ on here regularly puts together orders from a hatchery in NE that sells a strain of grass shrimp, P. Kadiakensis, that does well in cold climates and has successfully established in the ponds of several members on here; I just put two orders into three different BOW a little over a week ago.

http://www.pondboss.com/forums/ubbthread...true#Post178742

Keep no bass - none. You want the bass to overpopulate because then they keep the bluegill well-thinned such that the bluegill that survive the bass gauntlet grow several times faster than they would in a pond in which there were more bluegill competing for food. The bass won't get large, but your bluegill will grow like mutants and within two or three years will average almost as much if not more in weight than the bass.

As far as pellet size, if you stock fingerlings, you would want to feed whatever pellet size Aquamax makes for fingerlings; I don't know the name of that size but they have sizes for everything from fry up to LMB pellets. After a few months when the bluegill reach 3", you can feed Aquamax 500; when a good number of the bluegill reach 6" or better, you can mix in 600 half and half with the 500.

You can feed up to three times daily in the peak feeding months, probably May through September in your region; I'm currently doing this in multiple ponds and the bluegill feed like piranhas, and are growing pretty fast. If the fish start tapering off in their enthusiasm as the water cools, you scale back to once or twice a day. Then, as you noted, when the water temp drops below 55, they'll go off the food until the following spring.