I'm in the middle of designing a custom PC desk. Will be using 2-420mm rads. If rads are in sealed encasements (except for filtered intake / open exhaust ports), do the fans have to be mounted directly to rad? There would be no angles for air to flow around. Straight in / out encasement. I don't see how it would impede performance. It might even improve flow by removing center dead area of fan spindles that usually sit directly on rad. Thanks in advance.