I'd like to get to the bottom of the lighting issue here. If someone were to have a 400watt hps in a 4x4 area, would they DOUBLE their yield by adding an additional 400watter(using lst method, so not worried about the penetration issue), with all other factors being equal? Or what would a realistic increase be in yield? I'm trying to figure out if the cost to yield would be worth it in the end.