I did some of this years ago when I was managing a factory. If your heaters are thermostatically controlled, if the first one is still on when you turn the last one on, you still have the same peak demand. It you can leave some of them go until the first one cycles off, it should help. If the meter isn't working right, it will be tough to make a logical plan work.
Our peak came about 2 PM. We trimmed it by moving as much as we could to second and third shifts. Much of our operation ran 24 hours a day, but some smaller things didn't run all the time.
If you have heavy motor loads, you can reduce power usage by installing capacitors. Do you have anybody to advise you on that? Your power company may.