I saw a show yestereday on them. O'Neil Outside, he was fishing for them in a pond in central Georgia. They were huge. He said they got htem from Ken's Fish Hatcher. I think it is the home of the Goergia Giant He siad that it is about the 10th generation that they start going down in size. I don't know but would like to catch some 2 lb gills out of our pond. Said they were very aggresive just had to get the bait near them. This pond had only been stocked for 2 yrs and they were already 2 hand sizes. He could hold them and they would cover both of his hands. You might be able to look up the hatcher or his site and get more info.
If in doubt, cross their eyes!!