I hope you got resolution!! I’ve done it both ways. The times I’ve used my 4 inch fan and filter, it was placed on the floor. It struggled to remove heat but kept the smell at bay, but had to be ran at full power. Now I have a 6 inch fan in the same 3x3 tent hung at top, it’s on 30-35% speed and my temps are much better and the scent is negligible. For all the 3x3’ers out there a 6 inch hyper fan will allow you to be the weatherman/woman. It’s a Godsend.