you can use plastic dye but it still adds some weight to the fans so its not really recommended but hey, for 20$+ a piece you would think they could make one not brown. With that kind of investment into fans you should like the way they look.
Yes Push Pull on radiators is a different topic. That makes a good deal of sense on a radiator with the space in-between being restrictive an extra fan can help if your fans are not optimized correctly or don't have the horsepower to force that air through. The Noctua really fall short here the NF-A14 has a max airflow of 83 CFM and a high static pressure rating for its RPM 1.51mm/H2O but overall just doesn't cut it. For silence its a great fan, for performance it loses to a 3$ Yates loon. For a radiator its all about static pressure the NF-A14 Industrial 3000 RPM version for example has 10.52mm/H2O that's crazy. With fans like that Push pull loses its appeal as adding fans would lower temperatures by such a slight margin. price to performance is totally lost. Ideally, what I have found regardless of fan size 140, 120, 180mm, the best sound to performance is around 1800 RPM and the best performance is crowned to the thickest framed highest RPM fans. (Static pressure is increased with the depth of the fan blades) For single fan on radiator usage I've found I want a SP rating of 2mm/H2O or greater. No cool science on that just my experience.
See it doesn't look bad with window on looks normal
I don't understand what the statistics you just said so the noctua aren't good on the radiator? You see my fans how should I rearrange them for best performance? I also have 2 really awesome Thermalright 140mm but have stupid as he'll month on them the screw holes are space like a 120mm so I'll have to custom mount them if I use them
what I said was the Noctua NF-14A has a good performance for its RPMs but low overall with a max airflow of +/- 10% 83 CFM with a 1.51mm/H2O these are the official specs from Noctua. When you compare these specs they are only middle ground but the fans are among the most expensive on the market. A 1.51MM/H2O is not particularly great for a radiator and 83 CFM is not overly impressive for air flow. The only thing the NF-14A has going for it is that it's sound profile is favorable.
For 120mm fans a static pressure rating of 1.51mm/H2O is horrible. there are fans that are just as quiet that boast over a 4mm/H2O rating; so yes for radiators I am saying besides Noctua's industrial line all other fans made by Noctua are overpriced crap.
Science includes thermodynamics and aerodynamics for a reason use them!