Would you be hanging the cooltubes vertical on the mover? I think that would be sweet, and have stadium like on either side. I have seen something like this with excellent results. I wish I could give you my 6' mover. In the "Best deals" thread stickied in Grow room setup and design, there is a link for cooltubes for $65 including socket, cord and reflector..... THat fan would def cool 3 tubes. Sounds like your not using 1k HPS? that fan should cool 2 1k HPS no problem. I have veen wondering if which/ if any cooltubes are stackable. Air cooling on a mover can be a bitch. Hence why I retired my mover........
I think I would use and inline booster fan to draw air in.....cheap, and will do the job. Run some ducting with bends in it on the inside if light escaping is an issue from the outside.
Are you thinking 400s, 600ws, or 1000ws.
ANother reason I ditched my mover: Light was not very well covering when the mover was on opposite side. I put my 1k in a 4' parabolic and could cover the same area. If it were me and I was determined to use a mover....... I would add some stationary supplementary lighting as well............ THen you should get the most out of the mover, and light concentration. With my mover originally I figured I would end up with very airy buds etc...........