I spent a lifetime chasing those things around up here. They are my fav-o-right fish to catch. I have my best luck using bite size chunks of whole frozen shrimp.
Cats are my favorite, too!! I'm usually a nightcrawler guy, but one of the biggest channel cats I ever caught was on a shrimp. I had a bag of them left over from a day of dock fishing on the Gulf. I kept them in the freezer for a couple years then decided to try them on channel cats.
I caught that one in the middle of the day under a bridge up on Lake of the Ozarks. It was probably twenty-five pounds...fought like a freight train.
My biggest flathead was on a nightcrawler. That was on a creek off the Missouri River. It probably weighed thirty-five or forty. I almost always use nightcrawlers. I keep a worm farm full of them in a little refrigerator in my work shop. I've had good luck with big grasshoppers on my pond, too. I've had channel cats hit them on the surface before!