Max, I know this is gonna seem like I am pushing lights on you and I am sure you are fine with your setup but since you are talking bout adding MH to your bud room to get added UVb you should check out the light I am using it is and EFDL, aka a fluorescent on steroids. It has a lil uvb and a pretty tailor made spectrum for plants, and it takes less btu's of A/C. Other bonus is the thing has a decade warranty, no joke. I am going to have this thing till I go to have kids, maybe pass it on to them lol jk. Oh and their customer service is the best I have experienced, quick and prompt. Hope you think about it, they are not cheap but once you factor in bulb swaps, ballasts, and a hood (know you make yours but just saying), and A/C cost over the life of this lamp think you might like it.
They say it is comparable to a 1000, but a 600 is more accurate with my experience. Sorry if ya think I am spamming lopez, saw max's post and figured he might like to check it out,