For your tomatoes you can grow a stockier transplant with a daily
brushing the tops of the plants. Check out this page at cornell,
complete with videos on how to do it:
I don't have any experience with 250 watt systems, so I will leave that
to someone else. 3x3 sounds reasonable for a new bulb, maybe iffy for an
old bulb with no natural light. Be sure to use white "walls" on all
sides to help bounce light back so the plants are not all leaning into
the center.