cool tube cfm vs main cfm?

big wardrobe 30c/f

in upper section i have cooltobe with vent ... fan can be set to pull air- 100cfm inline fan
in main compartment i can push air tofrom bottom - 300cfm squirl cage fan

i do have an access to:
1 thermostatic continuous flow speed control unit

it will be important to be able ON and OFF for CO2
hmmmmm... .. .? im totally lost

am i missing anything?
which fan should be bigger ...cooltobe of small veg. compartment

bump

ps .just realized untill edit this post did not make any sense.
hopefully its more clear now.
hay