Hey I posted in your other thread.
Your intakes should be 2x the volume of your exhaust for proper negative pressure and efficient passive extraction of the heat.
If your exhaust is a larger volume than your intake, than it's trapping heat inside the tent and not able to efficiently pull it out.
Example: If I had 12" exhaust, i'd want 24" intake or equivalent.
I see, so you are talking in terms of volume and not CFM?