I don't have any practicle personal
experience so take that into consideration. But the majority of advice I see in the DIY
section says that cooling is more efficient if the fan draws air out.
With this particular canopy I think it would be even more applicable as the vent holes are directly over where the MH
will go, therefore draw cooler outside air directly past the bulb to cool.
guess it's time for me to google some thermodynamics info :o)