An AI Sol will not cover a 24x24 area. I have seen enough to know that. MULTIPLE people in my club thought they could get away with one for every 24x24 area. They all have additional units now because the shadowing was horrific with only one unit.
Two units cover my 120 gallon. Sure there are some areas where I couldn't grow SPS, but I actually enjoy that as I have places to stick less light demanding corals like acans. Some people may want to fill their entire tank from edge to edge with high light demand SPS and then I would agree that they won't cover the area adequately. However, to say the light is horrific is a little stretch.