Hey BH,

You can use any configuration you want. For veggi growth use the daylight bulbs that are more blue then red usually called "cool white" these will sometimes help keep your plants from stretching as much as the warm bulbs usually called bloom tube or something like that. I do very well growing under normal flourescent light during veggitative growth but I then move them under 1000 watt high pressure sodium. I would imagine though that you could just change your bulbs when you go 12/12 to a warmer type. I've never actually allowed them to flower under normal flourescent tubes but I suppose it works. The more light the merrier but just keep them as close to the plants as possible. Like 2" or so away is good and they will do fine for the first 3-4 weekish.

Best of luck,

Herbus