Batwing placement

I think I am going to use a batwing. I would be using it in a tent with a rectangular footprint. Should I arrange the bulb and reflector so the bulb is parallel with the long side of the tent or perpendicular to it?

First you should not get a bat wing get an air cooled hood. Your Gonna have way to much heat from light. What watt are gonna run? I had a 400w light on a bat wing style and the heat was to much, I had to keep raising my light so my plants stretched. Then I got an air cooled hood and 6inches from light gets me about 76 deg with a carbon filter and 400cfm inline fan.

i plan on getting a 250w with batwing and cool tube.

Go perpendicular, the wing helps bounce the light out.