Remember to consider your fans power draw when calculating headroom on the PSU. I think 120mm fans run around .33a on avg - so maybe about 4w each? If you’re really pushing the limits of the PSU, your best bet is probably an open air rig w/ good spacing, and an external cooling solution if possible. Here’s my setup for example - the 8x64 rig is on the left. The spacing alone is generally enough to keep these reasonably cool (40-45c) even at 70-80f/21-27c ambient. The cabinet is more for noise suppression and dust control (this is my garage/workshop too!) but the airflow helps on those summer days when temps get up significantly higher. Many people just point a box fan at their rigs. (btw, the fans on the one rig aren’t necessary, but I didn’t bother removing them as I had the power headroom):
There are different solutions for each case. For example in my garage im using 2 pipes - one for remove hot air and one as inflow. Also, i often see rigs in boxes with 120mm fans both side.
So your solution is nice but for your conditions.
The point was simply to consider moving cooling solution power load off a nearly maxed PSU (and that sufficient spacing can make a huge difference.) I offered my setup as an example, not the one-and-only design.