I have an Amerifan brand 8" blower with a 8" carbon. On the intake side it has a 8" adjustable elbow with a 6x8 reducer. 6" duct running to a 2x4 tent. All three tents vents are open with the blower on the lowest speed.
It vacuums the sides of the tent in. I have to grab the flab door when unzipping it to open.