Rapala Magnum lures are a great alternative to spoons and sinkers when trolling for lake trout, especially in the deeper waters where these fish hide. Their ability to reach great depths, natural action, and ruggedness make them a great choice for the conditions you describe (30-45 feet deep, 2-3 mph). They can be a great addition to your trolling toolbox, providing an effective solution for targeting lake trout and increasing your chances of success.