To get the full beinifit of T5, you need to get the parabolic reflectors.
30 inches is an akward dimmension for florecent tubes. I think the best layout for you would be 4-6 staggered 24" bulbs. Each bulb is 24 watts, so that gives you a total of 96-144 Watts. You would likely need a second ballast to support more than 4 bulbs. I'm not sure how wide those reflectors are, you might ask your supplier before ordering, so you can figure out how many you can fit in your hood.
There is a smaller selection of T5 bulbs than T8 or T12 bulbs, but the energy efficiency of T5 is difficult to beat.