Hey,
Seems like you got some decent wattage for a pretty nice yield IF you use your space adequately. I'm assuming you're limited on your vertical growth because you mentioned a screen. I'm gonna go out on a limb and assume you're doing a SCROG type of grow. If that's the case then you should definitely start training your smaller plants until you clear 1 ft from the base of the plant. I say put Very carefully start bending the top of the plant slowly underneath the screen. As soon as any of your tops start poppin up 3-4 inches from the screen pull them down underneath the screen. Keep on doing this all thoughtout vegging until your whole screen starts filling up. To help expedite the filling out of the screen I suggest topping your main shoot to produce more lateral growth. After the screen is filled out , then you could swith to 12/12. Good luck!