well, to be honest with you, you may be disappointed in your end product using those lights, the issue with those bulbs is they don't penetrate much, and the lumen output suffers greatly when the plants are not next to the light, if you have the means I highly recommend either a 48" t5 setup with four bulbs, or a switchable 400/600/1000 watt electric ballast that can do MH as well as HPS bulbs, reason being is I PROMISE you'll want to upgrade in the future, and this way you can not only go from MH to HPS bulbs when switching to flower, but also if you get a larger room you may upgrade to 600 or 1000 watts also.
Its expensive, I got that, but to get the results you probably desire, i'd go with a HID system. As always, this is my opinion.