Hell yeah! I am Union too Brother! I used some relays and photo sensors to turn my exhaust fans on and off. Then I realized I could have used relays to trigger EVERYTHING with 1 timer. You Sparkys got some cool toys.
OK. IF everything is assumed we need to think about the BTU (heat output) output of the bulb and the capacity of the air to absorb that amount.
From a quick google one watt equals 3.414 BTU. So 600x3.414= 2048.4 BTU. Not exact but close enough for our purpose.
Now it gets complicated because the amount of heat the air can hold depends on the humidity. But .018 is close enough. .018 BTU to raise 1 cubic foot of air 1 degree.
2048 x .018 = 36.864 CFM
So to theoretically stay the same temp, you need 37 cfm. But that is only considering the heat of the bulb, not the radiant heat produced or the heat load that is coming from outside on a hot day( which could be substantial).
From my experience with 600's in a cool tube, I found 75CFM to be a good number for my old 4x4 tents. I had three tents each with a cool tube. 8" insulated duct from the cooltube to a metal duct with a carbon filter inside. Through carbon filter, through 15' of 12" insulated duct, through the 6" 440 cfm fan then out a 7" bathroom fan vent that was in the wall.
Each of the three cooltubes pulled about 100 cfm, I measured them with an industry standard air measurment device. Because I had oversized duct the one fan could do it all. At normal pressures, 6" duct will move about 100 CFM, 8" is about 200, 10" is 300- 400 and 12" is about 400 - 500. Significant performance gains can be had by changing to larger duct. Also Insulated duct will get the heat OUT of the building. Otherwise the duct is a huge radiant heater.
My advise is to get ready for this summer. It gets hot fast with this hobby. You may be able to find insulated flex duct and all the reducers and stuff at home depot or lowes. If not just call a heating contractor. They can get all the stuff and have stuff custom built if you need it. Its not as expensive as paying for nutes and electricity and then cooking your whole crop.
Figure out a way to get the heat outside. I had duct hanging from the ceiling, running from a bedroom, through a bathroom. Whatever gets it done. Put the fan as close to the exhaust hole as possible. Then run the biggest duct you can to your cooltube. At least 8", bigger if its a long run from the fan to the cooltube. Hook directly to the cool tube, it will still pull heat out of the tent and its the most efficient way to cool the bulb. Also lights on at nite helps with the temps.
I am horrible with written communication so I hope this makes sense.
And Trailer Park Boys is AWESOME! "Its just a big kitty! I know all about kittys!"