Keep in mind that a current sensor is only going to let you know if the current draw is over the set amount. It isn't a power measuring device like the Brultech. It's either going to be reading the device as on or off. Due to this fact, you would probably be OK just monitoring 1 leg of the oven because it will probably be enough to let you know if it is on or off.
It is a double oven.. I wonder if it is 1 leg per oven...