Help, my seedlings won't grow anymore!!

Ok, so I returned the 250W Hps today, couldn't afford to wait for the temp to drop and risk killing my plants. Exchanged it for 6 4ft T5 fluorescents. Right now I have them set up vertically against the wall because its like 2 inches too long to hang them up, even if I tilt the set up at an angle. On the box it says you could set them up either hanging, horizontal, or vertical, but I just want to make sure this is going to be good for my babies.

transplant them into bigget pots so that the soil level reaches the leaf with about 1/8 of an inch of stem showing.