Could you put the 1000w on a light rail?...If not, then you should perhaps look into some extra lighting, as there will probably be a couple spots that don't recieve light very well. You'll be achieving 35 watts per square foot of canopy space with your 1kw, which isn't bad, but you'll see much larger yields if you can bump that on up to around 50w per square foot.
I just recently added 2 315w CMH lights, one on each side of my 1000w, for a 5x5 space and I'm really happy that I invested the extra money! If you're strapped for money, then do what ya can for perimeter lighting. CFL's will work in a pinch, or cheaper chinese made LED panels.