The stove has an off position that being 1 and several other options being so if I wanted something halfway in between I'd use 0.5 this means that you can control the enchantments output to a limited degree, and the spell can also be linked to as many enchantments as you like but maintaining the link takes a very small amount of magic, the more links you have the higher the magic drain and if it exceeds what the environment has, or the power source can provide the links will degrade and fail.