So Ph what works better? Pull pull or push pull or is it too close to much worry which you choose?
My 'guess' would be that you don't need the open item between the two fans, that putting two in a pull pull scenario increases pressure, much like multiple compressing fans in a turbojet engine, they don't need a separation between to do that job, but there would be a drop in efficiency, ie the fans won't double the cfm througput.
My additional guess is that push pull would work about as well, IF using a shroud on the input fan. But many users who do push pull don't put a shroud on the front in many of the design screenshots I've seen.
So to continue this guess (PH your input could be very useful after this), the rad, shroud, pullfan, pullfan design and the pushfan, shroud, rad, shroud, pullfan designs should come very close to each other in efficiency but the thicker the radiator, thinking that would decrease the airflow through it, the more likely the pull pull will work better because the actual pressure increase from two fans working right next to each other would be better to overcome the thick rad pressure drop than push pull. The further benefit is the need for one less shroud in the lineup decreasing size.
All guesses, but the scientists are free to confirm or refute
