I've never seen someone else use this trick (highly doubt i invented it), taping a carbon sheet to the entry of your AC I use this in the room where I smoke, in a grow tent the ac without a real carbon isn't enough to keep odors away (it doesnt smell when used in conjunction with a real carbon filter) but for smoking I think its fine
i used to run a 400 watt with a 4" fan, temps were okay but too hot during may to august(my ambient temp (for the intake)during those time are around 26c / 85F) so no matter how strong my fan is i cant cool that)., atm im using a 600 watt still using the 4" fans but i use the ac
with the ac you actually have a control over your temp like its colder inside my tent then outside it, something that would never happen if you simply had an inline fan (im probably not teaching you anything, but they only move your air it doesnt cool it)
you might have seen this before, but it never get posted enough (its approximation but its pretty accurate)