Need some input on lights..

Ok well I got just a quick little question. Right now Ive only used 400w and 1000w lights. Love my 1000w and the buds its produces. Well I am about to start another grow in a 4X4 hydrohut; 30 plants sea of green style. After talking to a fellow friend he advised me that his results are pretty close to being equal when using 600w vs. 1000w. Hey tells me I should just use a 600w instead of the 1000w. Power consumption is a big thing to me so I like the less watts being used. I will be using a 6000btu A/C, air cooled hooded, 450+cfm inline fan, 175cfm squirrel cage fan, and full Co2. So heat from either light I choose will be no problem. I know for fact the 1000w is better; i.e. more light=quanity/density. i guess what i am after is, when looking at the big picture...heat, power consumption, 4x4 space: would a 600 just be more practical?? Would yeild suffer greatly?? Thanks guys any input would be great...

A very general rule of thumb is that your garden needs 50 watts of HID lighting per square foot of illuminated area. This rule ignores the shape of your garden, so the following is really a better guide:

A 250 watt HID will illuminate a 2' x 2' garden.
A 400 watt HID will illuminate a 3' x 3' garden.
A 600 watt HID will illuminate a 3.5' x 3.5' garden.
A 1000 watt HID will illuminate a 4' x 4' garden.

a 600 will give you roughly 33 watts per foot in the hut, you can grow some good buds with that for sure, your best bet would be to keep them as close together as possible under the light, you will still get a good harvest under the 600