I bank fish in the Mississippi at the dam in Alton IL. Sounds like a similiar situation to you. I only use flat bank sinkers. I use 4 to 6oz depending on the current. I think they hold the bottom better than regular bank sinkers. I also believe they are less prone to get snagged. But around most dams I think the chances of getting snagged are very high so I would recommend using a lighter line to attach the sinker so you only lose a sinker. If you are only looking for a sinker to dig in and hold the bottom I would use a pyramid. Good luck.