also you could do another room if you only do flower in each. i veg and flower same room so i would need a different setup or need to adjust timers differently or something. if you made it do two separate rooms then you would need a system that would sequence the ballast though four bulbs 3hrs each then it would flip to room 2 and sequence though the other four bulbs for 3hrs each before returning to room 1.
my theory is plants can only absorb light for so long out of the 12hr day so indirect is better than wasting lumens above plants that have had enough. if the bulbs light for 3hrs eace i'd say thats long enough and besides