You need some more height to consider a large HID. For that space, a 600 air cooled over a sea of green style grow (rooted clones flowered at only 4-6" tall) is a better choice. Teh appropriate footprint for a 1000HPS is 5x5 with at LEAST 6 feet of head room and a 6" blower on the exhaust- not a duct booster either, a badass canfan style blower. Happy growin.