You should be able to grow very large bluegill even with focusing on the bass; something you might consider would be stocking a couple tiger muskie to keep the small bass thinned along with the smaller bluegill (recommended in a recent PB article). Feeding the bluegill with an automatic feeder will make a big difference, both for them providing the bass with more forage and growing larger themselves.
I would suggest skipping catfish if you think you might use a feeder, as they'll hog most of the food and physically knock the bluegill out of the way when they (CC) get larger so the bluegill don't get much of it.
