So I recently found these massive 150mm fans used for commercial applications(As they move over 150 cubic feet of air a minute) As I haven't done much with cooling, I don't know what position to put them in. Is it a good idea to put one on the top and another in the rear case fan position? I will only be turning them on when components get hot, as they are loud and old(They were made in West Germany) but are extremely well made(100% aluminum blades and casing) and have been used for less than 20 hours. What position should I put them in and should i use one or two?