400w mars 2 LED light in a 2.5x2.5 tent. ???

[Gordo41]

this light is sepose to cove the whole 2x2 foot print but the light falls off quickly once you move out from right under the light.
I want to add another 400 light to help fill the space,, but my question is... what would be the best configuration of the lights to get the best coverage.
the lights are 11.5x11.5" the tent is 2.5x2.5' or 76cmx76cm