I'vs always been a "fan" of pulling air thru anything rather than trying to push it with the Dayton squirrel cage fans. #2 would be my choice. That allows the possibility of creating a negative pressure room and that will easily allow you to totally control the incoming air, the temp, humidity, and co2 if used. All you need with a negative pressure room is an envrionmental controller. That will allow you maintain the best growth conditions day or nite, winter or summer. Good luck