Next grow - 600w HPS flower, 250w veg?

Hey, guys. I am plannning my next grow and would like some advice. I am currently growing three white widows from Nirvana under a 250w Dual Spectrum HID. They are about 6 weeks in flowering and looking OK. I think the 250w wasn't enough for descent sized buds. The grow is also in a confined closet, so conditions arn't ideal. With my next grow I am planning on building a grow room in my garage. Room isn't a problem there. I am hoping to grow three different strains. Possibly Greenhouse seeds' White Widow, Nirvana's Aurora Indica, and maybe a sativa, like one of the Arjan's haze from Green house seeds. Does any one have any expierience with the Arjan's Haze lineup? I will get 5 feminized seeds of each. I am wondering if my 250w will be enough for 12-15 plants to veg for a few weeks and then a 600w HPS for flowering? I would like very big buds, so would 600 watts be enough? What would be the most I should put under a 600W? Also, does anyone have some advice on the strains? I would like one very medicinal, "couch lock" strian, and a sativa. Thanks! If you want to see my current grow, I have a thread you can look at.

bumpbumpbump

bumptybumpbump

Yo man I think you've put a bit too many plants in the one area! What size is your cabinet? I've got 3 ak47 clones vegging under a 125W CFL and am going to put my 600W in when flowering! I'm even thinking of getting rid of my 600 for a 1000W badboy and using that instead! When you planning on throwing into veg?
Peace