Sounds like you're good to go. Still, I've seen setups where there were multiple ground locations that were causing a few gremlins with electronics.
Saw in some ad-magazine that the new Lumateks not only allow you to dim the bulb, they'll let you use lower-wattage bulbs as well. 400W will drive a 400W & 250W, 600 will drive a 600w & 400w (at 600, 400, and 360), and the 1000w will drive a 1000w, 750w, & 600w bulb.
I thought that might be useful for those who vegetate with less light than they flower under. I assume (could be wrong) that the 600W will drive a 400W MH which, while producing less lumens than a conversion bulb rated for a 600w ballast, is a lot cheaper to purchase.
Probably be a popular seller.