Well I'm 29 days into flower and both bulbs are pretty much HPS, my 400w is a MH ballast with a HPS conversion bulb in it, and the 1000w has a bulb that covers about the top 1/3 of the mh spectrum and about 3/4 of the hps spectrum. I've just been keeping the best plant under the 1000w, even though it's not a perfect spectrum it's a lot of intensity to fill out my buds. I do rotate my plants around all the time though so they are getting all sorts of light at all angles.