Anyone ever use the ipower brand? They have them on ebay for pretty good prices for a 600w dimmable setup, is there a big difference between using a air cooled hood compared to the cool tube style?
Always remember that you get what you pay for esp. with ebay, not saying don't get something, just saying research this stuff as much as possible before you make a buy...
air cooled hoods tend to give better light footprints than the cooltube but you also have to balance cost with benefit: if you're in a space with a 6x3 footprint you can stand to have a few plants so maybe a hood would be better; then again if you're trying to scrog the cool tube would be fine, just match its footprint with the screen.
however, never underestimate the power of diversity in your light scheme....you might want to check out the club T5 and LED without LED threads and see how productive some growers have been by mixing T5 panels in with their HID flowering setups to get a more complete light spectrum on their plants (better quality buds from trying to match the PAR /PUR of the sun, more yield and deeper penetration from the HID).
just my thoughts on the matter....of course the primary reason i've seen for people to go with T5 (and the reason i choose to go with T5) is for their low heat production which doesn't seem like that should be a huge problem with your space:: what are the ratings on your fans in CFM?...If you really are concerned about heat buildup with 250 and 400w hps in that space, look into T5s they're pretty sweet and depending on your proclivities you can set up a t5 grow for less than your HID setup and get some good medicine.
be easy