I have also considered using 10"x6"x6" register boxes on the intake side instead, and this would cover just the fans (plus a small gap to the side that I would shut with foil tape). I would add holes in the cooler lined up with the PSU intake vents that I would fill with PVC piping to allow intake air to the PSU. This would allow me to not need a 8" to 6" reducer on the intake side. I am not sure how long the 10"x6"x6" register boxes measure, but if we assume it is the same size as the 10"x10"x8" register boxes then that makes it also 6.5" and reduces the total size of this enclosure to be ~31.5"