OK, so, you are looking to fit a few more pots in there. If that's the direction you're wanting to go, I would consider adding several more bulbs to your manifold. That, or maybe just veg what you already have going for a bit longer. Maybe upgrade to some bigger pots, and crop them out as best you can. A good general rule of thumb for flowering wattage is 50 watts per square foot. 60+ is better.
Keep your bulbs as close as you can, and watch your temps!