If you’re just going to have 1 clutch then I’d recommend just building an incubator. Even if you don’t want to there isn’t much you can do wrong. For the classic heat tape incubator (I don’t know anything about aquarium heaters… yet). If you can find a small styrofoam cooler, then it’s $7 dollars in heat tape (non-affiliated link). $10 for a thermostat and you shouldn’t need a fan with only one clutch.