Here is another approach.
On this grow I've swapped out 4, 300 watt viperspectra LED's with 2, 315 LEC's. Certainly not a scientific experiment, but this is my largest grow yet. Had a bit of a heat problem but solved it with more exhaust and cooler air to the grow area that the tent is in. These Autos seem to be finishing up faster compared to previous grows, but I didn't manifold this grow, only LST and super cropping.
The 4 LED's drew about 520 watts...the 2 LEC's draw just a bit more at 696 watts. I really like the fact you can "see" the true color of the plants.
I've been through 600 watt MH and HPS, 4 300 watt LED and now the LEC's. I think I will be staying with the LEC's