The 132 and 120 boards run heatsink free. The lower power level and diode spacing allow pcb to provide enough cooling.
For a 4x4, like 4 288 boards at 2100ma. Running small light in big space is a little more difficult because you lose reflection around edges of canopy. But three 260 xl kits would be pretty solid setup in a 5x5. They run about $350 each, you could start with two and add third later and use whole 5x5.