Fractal design r4 airflow and fan placement

[Jordanm]

I have three corsair AF120 quiet edition fans and 2 stock 140mm fractal design fans
Also I'm using the hyper evo 121 cooler

How and Where would I position them for positive air pressure
(so dust exits the case easier)

 

[qwerty987123]

two 140mm fans in the front
one 120mm fan in the bottom
one 120mm fan in the rear
one 120mm fan in the top