question about lights

[track]

I have 2 questions, one about lights and the other about food at the end of a cycle. I am currently working with 2-1000W bulbs on a small 8'x4' bed and I have heard about rotating lights and lights that are on tracks. My question is if I use one of the lighting above, can I reduce the bulb size from 1000W to 600 or even 400W and still not effect the plants. There are two different bulbs at this time and I have been told that the would do good with all spectrums of light.