2x250W MH and 2x54W T5 using 2x2 and plywood.
Because of the width of the T5 reflectors, I only have room for one bulb along each side. Longterm plan is to use the other ballast and 2x54W Daylight bulbs I have (for total of 4 T5), just would need to replace the current reflector with something narrower such as the Icecap SLR.
For airflow have a small (4") muffin fan in the basement, connected to a duct that comes into the side of the hood through the column, exhaust is just a 3.5" in the top of the hood on the opposite side. Because of the long duct, the airflow isn't that much but enough to feel.
old picture when using the NO fluorescents
