I've been considering airflow models for the lower heat chamber of the case.
Excuse the crude mock-up, I didn't have the time to model everything in SolidWorks. In the green configuration, fresh air is pushed through the front of the case and then pulled through each of the 560 mm radiators before it is exhausted out the sides of the lower heat chamber. In the red configuration, fresh air is pushed through the radiators into the ~100mm central area where is it guided by the front intake fan to an exhaust at the rear of the chamber. In the pink configuration, cool air is pushed through the first radiator, through the central area and is then pulled through the second radiator and exhausted from the side of the case.
I've been weighing the pros and cons of each setup. In the first two configurations, there is a huge imbalance between the number of intake and exhaust fans. In the red scenario, there are 9 intake fans and 1 exhaust fan -- in addition, the air will collide in the center of the case and possibly create a dead zone as the fan at the front may not be strong enough to push it through the length of heat chamber. This will give me a tremendous amount of 'positive pressure', but at the cost of having unknown fluid dynamics of the air in the center of the case which may get stagnant and super-heated if it is not exhausted quickly.
In the green example, there are 9 exhaust fans and only one intake. I'm not sure enough cool air is being supplied to the radiators in this scenario. The fans will be forced to suck air into the case through the mesh vents and then pull it through the radiators increasing the amount of dust in the heat chamber. The pink example is what I had considered doing primarily, however, the warmer air is being pushed through the second radiator rendering it much less useful at cooling the circulating water than a radiator with access to my 15.5 C ambient air (I wish it was colder -- one of those freaks that loves the cold). I may end up having to experiment with each configuration to determine the most effective way to cool the chamber.
I've also considered mounting one 140.4 in the base and one 140.4 in the top chamber as well as putting another 120.3 or 120.4 somewhere in the build in an effort to maximize cool air intake, but it will make for really long and ugly tubing runs and possible instability with all of the radiators mounted on one side of the case. Let me know what you guys think!