If you can afford to buy some air cooled cylinders, do it. If not, make them, find out here, www.overgrow.com
Hook up some ventilation ducts through your lamps, Ive never done it, but Ive read about it..
tells you how to do it on overgrow.. run air in, and air out..

You'll need duct fans leading outside somehow to bring in fresh air.. blowers, something to get the air in, and the air out
www.insidsun.com or www.discounthydro.com

As for vegging small plants, you will probably need less powerful lights.. those are way to high in heat to keep close enough to your plants, I'd say they'll grow, but not at full pace and you will probably encounter problems..
Skateboardingpunk420 Reviewed by Skateboardingpunk420 on . Need some help setting up the hp system for a full room !!! In about 1 month we will smoke my first own weed ...and me and my friend want to grow many plants for next growing... we want to grow in a full room. You can see room on attachment...can someone tell us how many 600W HPS Light's we need for that room full of plants...and how many plants can we grow in that room please? Rating: 5