I wouldnt use a 600w HPS if its your first grow. Thats a little dangerous without someone who knows what they're doing. I would typically use a 200w HPS for fast growing without the danger. If you get reflectent panels, your plants will grow alot faster, I forget where I saw the ebay light, but it came with a 250wHPS and 2 reflecter panels for 75$. I would suggest that you try to find a 250w HPS and atleast 1 reflecter panel to the side. If one side of the plants arent getting enough ligh, use the panel to reflect the light on to it.