well depends what stage you are in, you might want to start a little veg room where you can just use blue 6500k cfl's then transfer to your mj to your hps, then add a few red 2700k cfl's around the sides, with cfl's try to get them as close to your ladys as possible, within 2-3 inches, use the sides of the cfl's as they give off more light, do not worrie too much about heat from the cfl's as they do not have much, there is tons and tons of info on cfl's, they are all i use, easy to get hold of, cheap to run, not many issues, just remember to not go too high with watts, genrally stick to between 20-30 watts and as many lumen as possible, do not bother with the ones the size of your head they are a waste of time, do you have sufficient cooling for 2 600w? would it not be easyer for you to get 1 1000w and get a reflector with adjustable wings?, just tryin to save you money.