I would veg then under a t5 but for flowering, then get yourself a hps.. I got a 600w hps for 200 on ebay. Invest in lights, the love more you show the girls the more love they show you.
Actually, it would be easier and cheaper to put in the HPS and forget the T5. Why buy two fixtures and have to switch them out in mid-grow? Even better, get a MH bulb that will work off the same ballast as the HPS and then one lamp will take you through the whole grow. A 600w would do a good job on 6-10 sq ft, if you want to use more space than that consider a 1000w. And either way, using a cool tube or air-cooled hood will mitigate any potential heat problems.
so this 600 WATT HPS DIGITAL GROW LIGHT w/ XL HOOD 600w BALLAST | eBay and would a mh bulb work for this
Yes that's the idea but the yoyos they come with to adjust light hieght suck. Also you wana go for a sealed hood. I had a 600w hps in a 4x4x6.5' tent and with a sealed hood and an inline fan, yet the temps were at 79-84 which isn't ideal. So an open hood I would imagine give you a tougher time.