ok,
Standard cool tubes are 6 inch round and about 22' long Hung horizontal gives you a foot on both ends. Go straight back and up both sides. Cut holes in the back corners. I would say get a duct fan, they will keep the light cool. I use a 110cfm and it works. Anyway one on the right lets say is intake and the left exhaust for the light.
May as well cut another 6 in hole in the center and get another one, use it for plant exhaust.hang scrubber outside of cab. behind it. Next cut intake at the bottom of the cab for plants
I have done it a couple times, Check out my cabinet journals.
Only I did it a little different, I built my own cool tube and used dryer ducting.
Heres a pic.