8" inline fan

First time posting, how's it growing everybody? So I'm' about to start construction on a 10ft high, 7ftx18ft room. It's in the back of my uninsulated garage. I've got 3 hydrofarm raptor hoods 8". What's the best way to cool these, without letting the neighbors know what's going on? Quiet is key...

I have 2 600w not air-cooled. In a 4x8. I can't find any posts apart from 2 tents one fan. I just wanted to know as I have 2 and whether it'll be too strong and curve my tent walls in or it'll be just right. Cheers Happy blazing