good to see your getting advice other then what i could throw out. everyone seems to have the same thought as me. the space your trying to pull is a bit small for that many plants

since ur getting beans (always the best to learn) start with one. as long as you take care chance of males are pretty fukn slim...
spend your budget on a cfl/cab this will get you bulb swaping control. hid is GREAT dont get me wrong. i run 2 400 on the exact plant you are wanting in my vegroom. but for your personal quest id say this

keep your setup 2x1xthe hheight

make a diy scrubber.! buy some platform (wood cut to near lateral area) chain it up so u can rais the platform(canopy) mount all cfl or tubes. cut a hole so u can mount a fan suckin air up toward your ceiling/venting.

this should cover one plant from start to finish. LST and take things slow, id say an ounce for one is much better then the future quarter per plant it seems like u might run into....