I don’t think trolling a leech around a lake is all that fun. I’d rather take a crack at reading what the lake is telling me in regards to weather, temperature, depth, structure, food availability, etc. then setting up a presentation that puts me into fish. But that’s just me. If trolling a leech is the best way to do that, so be it but it’s not something I usually do first. Since trout eat so many of ‘em, chironomids are often a good place to start, especially in the spring with the sun on the water.