conversion bulbs! quick question

ive got a grow tent and its 6ft by 6 foot and 4 600 wattHPS over 36 plants.
but i want to use MH for my veg growth and if i buy 4 400wMH conversion bulbs will they work in place of the 600w hps bulbs or will i need to buy the 600mh conversion bulbs?

i hope not because i think its overkill on lights in there as it is.

600w ballast uses a 600w bulb

technically you can use any watt light bulb as long as it doesn't go over the listed wattage. So a 600watt will run a 400watt bulb no problems.
but shhhh.... it's a little secret some have yet to accept as fact.
Also MH bulbs will work with Hps ballasts.

wow... trying to price it all up now . is it better to buy the full setup lights hoods and ballast all in one or buy them all seperate and put it together yourself.... its a little tricky trying to piece it all together on paper... and its looking pretty expensive too

It's easier for me to buy entire setups because I get package deals that way.

easier for YOU or easier for everyone? in my local hydro store its like 600pound for 4hoods 4 ballasts and 4 600MH bulbs.. ouch