what reflector works best with a cool tube for hps

Hi i made a homemade cool tube out of a Bake a round,
i have an open hps with a batwing relflector mounted to it by a bracket...obviously im going to have to take the light off the reflector,to make a proper cylindar with the duct.
Once i have my cool tube up and standing,,,can i just hang my batwing reflector above it?? i mean i never see people doing this...is there a reason? people usually hang something right over the tube ONLY. mine will cover more ground then just the tube obviously,,,you help is appreciate

I am in the process of doing the same thing with my 150w hps. I was just gonna hang my reflector over my bake a round. I have also seen people just use the Aluminum tubing as a reflector/ air ducting. I have like a semi-paper tubing so I'm just gonna use the reflector.

I very interested to see if anyone knows example of CFM airflow for a CoolTube's. I bought 4 - 120 cfm fans and I'm hoping that one on each end will provide enough airflow. 2 fans just for intake.

Any comments would be great...Thanks

floyd: yeah sit your batwing above the tube itll be ok
av8tor: thats plenty of air flow through the tube but you want negative pressure to help with the stink id maybe keep 1 fan intake and have some more passive intake n stick the other fan in line with your duct to beef up exhaust just my 2 cents that neg pressure is better to elliminate smell exhaust somewhere inconspicuious or through a scrubber