Remixed anocweb's original model in order to allow a little more room for the factory screws.
If you'd prefer using a 30mm fan, there is a STL for that on the original model's page.
I printed mine on an Ender 3 Pro, somewhat modded.
Soldered the wiring for the Noctua NF-A4x10 FLX fan directly to the barrel connector solder points on the bottom of the USG's main board.
The fan requires no hardware to attach to the shroud, it fits right in rather snug.
The author remixed this model.