You should figure around 50 watts/sq.ft. - 7'x9'=63sq.ftx50= 3,150 watts. But that's if you could spread the 3,150 watts evenly, which you won't be able to do because the lamp and reflector have an effective footprint (the area they can effectively light). You can get a max 4'x5' footprint with a 1k lamp and rectangular reflector, or a little bigger than 4'x4' with a square reflector. Then you need to try to figure out how you can best utilize these footprints in the grow space you have. Light movers can be used to compensate for areas slightly larger than the ideal footprint, but you can't get too carried away with how much extra space you light.

Two 1k's would give you a grow area of 4'x9' if you used rectangular reflectors, and that would leave a little bit of room to move around in there to work on your plants. The reflectors you are referring to are called "air-cooled", so that's what you want to look for when shopping for reflectors.

PC :smokin: