Help me with lighting please!

I will be growing 6 plants in a space that is 3.5' X 4' (42" X 48")
Using either MH or HPS, what wattage should I have, and how many bulbs? I was thinking two or four, but I don't know the wattage I need.

Thanks in advance!

1x 600w HPS

400 or 600 with a cool tube

and get the mh conversion bulb for the hps fixture for veg