Hi Justin. Welcome to the site! Nobody else responded so I thought I'd give it a shot. Don't want to leave you hanging.
Haven't fished for cats in about two weeks, not because I don't think I can't catch cats but because I've been busy. Mostly I catch channels. For those I fish shrimp, night crawlers and liver & cut bait. Try to fish when the river is on the rise. Seems to work best for me. Also try and find some structure. Logs, brush, stumps. I've caught channels a foot from shore in flooded trees.
As far as flats are concerned I can only relate what I've learned here and there are a number of very knowledgeable folks here that can steer you better than I can. They seem to relate to temp. more than the channels so keep a watch on the water temp. Also live bait, chubs, suckers, bluegills, bullheads and even trout seem to be the bait of choice. Cutbait can also work.
Don't get discouraged. Keep reading this site and trying new spots and new baits. Hope this helps you out.
I would like to add to this post i have caught a lot of flats no more than a hundred yards from the bank