stinky said she was using 5" pots for most of the plants and 3" for a few of the fast growing strains and could acheive 30-40. the 400w hps should cover the tray fine and would work pretty well i assume. you probably won't get much penetration once to plants get taller, but if you are going for a SOG i would assume it would work.

how about that light stinky? and can you put mulitple strains in the same tray?

-shake