light help

Im looking for help with my grow room set up.Has anyone ever uses a MH/HPS Duel spectrem system.My thought is to grow four plants with a 800 in a 12" 2 gallon container.Would this be wide enough for any kind of strain?Would it be bad to use the MH and HPS lights at the same time for veg. and flowering? or would one bulb be enough for all four plants? Any help would be great!

i use both m.h,and h.p.s all through the veg,and flowering,not a duel but they seem to love it,many folk dont seem to like m.h but my plants seem to love both light spectrums for the entire grow.
others will no doubt prefer m.h for veg,and h.p.s for flower,but each to their own.

so how many plants can i grow with a 800W system with one mh and one hps bulb? would about 6 be ok at one time or more?