more intake or out take?

do you need the out take to be more or the intake? i have a 14 aircooling and a 12 for the in.. i think i need more out to pressurize the room but im was trying to figure out what size of fan would work. i was guessing 10 or 12? thanks

You normaly want more exaust cfms than intake, so you can have negative pressure in your room.