The two light tent is 2.5x5 its half a 5x5 so basically would use 4 box fans above bar lights (BAB). Seems overkill but I actually like it better in there vs 3x3. In the 3x3 it seems to be pulling air up around edges and blowing down like 2x2 of that 3x3 space.
The 2.5x5 the fans blow from wall to wall which I like the turbulant flow can feel with hands. Can use a piece of papertowel and see it lift when holding it out where youre gauging airflow. Either flops down or up because air is also being rushed to the fan.
I just have finicky requirements, they dont make a lot of 2.5x2.5, 2.5x5 or 3x6 or 6x6 tents. Just my luck. The 3x3 manages rh better with a big plant than the 2.5x5 if youre trying to stay below 45rh. Thats why I say every inch matters for plant growth and rh management. A 2.5x2.5 only a few inches wider than 2x2.
2x2 though.. Those suck for heavy users lol. Height matters too, 6’ tall minimum 6.5’ is best for the box fan and lights. Inline fan/filter will need to be outside of tent, you lose that perk. I was loving using the prefilter with filter inside tent to last forever but whatever.
Height also makes for easier/bigger plants, the way an extra 3 inches around a 2x2 can allow for such larger plant. I still dont get how, I grew 2x2 handful of times and struggled with full size plants, very packed. Even my second attempt which was better. Pruning works, I double my yield 2nd run.
edit to be clear the 3x3 the power of fan drops alot after the 2.5x2.5 mark. I like seeing and feeling the air, the edges of 3x3 have me worried. I wouldnt go any larger.