I used to fish a reservoir like that, what I found to work was using a 1-2oz bottom bouncer with a spinner rig pulling 1/4 of a night crawler. I tied my own spinners the same as I do for walleyes with similar set up only I use smaller hooks and spinner blades and keep them much closer together, like 2" or so. Often I'd make the snell 4' long to give it a little distance from the weight, not sure if it made a difference though.
The bottom bouncer acts as a poor man's down rigger, keeping the crawler at the target depth, then I'd just troll through the schools of fish. I didn't have a line counter, just kinda estimated a ran them at different depths. We caught a pile of them that way, way more than a slip bobber. Most of the time I wouldn't even get to fish, I'd be baiting and unhooking got the kids, they had a blast
