The lenses are 2 feet from where I plan to build my net. Majority of my canopy was kept within 12-18 inches. I honestly don't know what's the best distance, I mean I'm rocking 950+ PPFD in a 2x2, i don't think it even matters since the tent is absolutely slammed with light.Nice job how many feet is your above I got the t2 2100 about 1 foot above?