Your lake sounds a lot like my lake. My method in this situation is a fathead minnow (no shiners allowed) on a #6 eagle claw aberdeen thinwire hook with a split shot a couple feet above. Hook minnow through nose. Drop straight down or cast to where you marked them and let it sink. When that minnow goes wriggling down into the school, you will hook up every time. Something else I've noticed on my lake, is this time of year the crappie bite soft, like they don't simply inhale the minnow. They will only bite half of it, hold on to it, then try to swallow. I use the 5-mississippi rule if it feels like a crappie bump. Then just start reeling, don't "set the hook". But if it's a bass that bites, you'll know. They still hit it pretty hard.