2400w isn't that huge of a power consumption - I wouldn't worry about the electric company noticing or caring and rather go with whatever works for you. Run all 4 at night if it is too hot during the day or to save on power by using during off peak hours, or run all 4 during the day so you can check on them at the same time, or do half and half so you can run your washing machine anytime during the day without flipping a breaker...
As long as you pay the electric company they straight don't care, and again that isn't all that much power usage. My AC unit by itself pulls 2,600w and that isn't for a grow, just to cool my house. Space heaters pull ~1200w. Power company doesn't blink an eye if you run a space heater or two along with your big screen TV...