Outlet Cover, Minimum Size (includes FreeCAD file)

I was using an outlet box as an electronic project box. Outlet covers in the store were too large (and rather expensive). So I made this quick thing. The FreeCAD design file is provided, so feel free to use it to adjust the dimensions to your needs. The dimensions (mm) of the provided models are in their filenames (either 96.5x57x3 or 94x57x3). The corner radius is 3mm. The two holes are 4mm dia, countersink 8.2mm dia, hole spacing 83.34mm (3.28").