If you are really using that much up there I doubt you really need any
space heaters. I bet you would do fine with 60a. That is a lot. That
is 14,400 watts. How big are these griddles?

Good point. I won't need one of the space heaters whenever I'm using
the griddles. The griddles draw 12A each, and do release a lot of
their heat into the room. The other heater is needed, though, as it's
in a different room.