The Mars II 700 has a 2x2 footprint in flower. That is one good plant, any more than one and you reduce yield for each plant.
I personally would stick to one plant unless you plan to add another light later on.
I grow under LEDs that draw the same as your Mars, and have at least a 3x3 footprint and I still like one plant a light in flower.
Thanks @jingo What else shall I add to the 700 for 2 plants? I was thinking of 2 of the reflector 48's angled from the corners.