Hey Mike, this is a super inspiring build and I'm definitely going to take on a few things from it! I stumbled across this whilst looking for ideas with my nano S build.
I have a similar one in the works but on a z370i strix/zotac 1080ti mini arcticstorm. w/c components are similar, the z270i block also fits on the z370i so I'm going to use that. I'm going for the d5-res combo and will have the CE 280 at the front in push only (fans in the front). Thankfully this board has a USB2 header so I've got a Aerocool Project 7 hub doing the fans/RGB control (very cool little piece of kit - $25 RGB and PWM fan hub!). Sadly they got rid of the 4-pin RGB header on this edition of the board, and instead replaced it with a programmable 5v header for LED strips.
I wanted to ask how you mounted the top radiator, as I have the same RAM and I know from eyeballing it will cause clearance issues with the SE240+25mm high fans. How far did you mount it away from the standard mounts, and how did you do it? When pushed closer to the side window, only the screw holes from the far side of the radiator will line up for me. I was thinking of fabricating a bracket and screwing it in from the rear of the case, just to hold the radiator up on that side - I'm not sure yet. I already scratched the paint on my SE just from lightly test fitting it.. did they coat these things wafer thin or what!
I can't believe how difficult it is to find fans that have decent static pressure, are PWM controlled and use a standard 4-pin RGB connector.. I think that's the component I struggled with the most!
One suggestion I can make is for the moduvent, if you wanted to raise it up evenly to give it a meaner look (and some airflow to those top fans), some screws with bump stops over the mounts might do the trick.. I was going to try and do something similar. Something like this but with a larger rubber bump stop that you can cut to your needs.
Cheers for any information you can provide, and again - awesome build.
Sean