unsure of the lighting schedule

[Whaddya]

Hey Everyone.....I am growing (tomatoes) for the first time under a 460 watt bulb and I am unsure of the lighting schedule I should use, How long can you give the babies 24 hours of light (or should you) before they need to be on a more regular schedule such as 16 on, 8 off? What is the best lighting timing schedule? And when it's time to bud them, does the light need to be cut gradually or instantly cut in down? Thanx a lot for the info!