Mounting Ubiquiti UniFi AC Access Points

I recently had my new house wired, so that I could install my long-serving Ubiquiti AC access points onto the ceiling, with no visible wiring.  I noticed, after I hired an electrician to install ceiling boxes, that Ubiquiti's rotary mount has 2 significant flaws:

1. The holes provided for wall/ceiling mounting do not match either the US 2-3/4" or 3-1/2" ceiling box mounting holes.
2. The rotary mounting plate has a release lever that is almost impossible to access, once it is mounted on the ceiling, as the level is almost flush with the bottom of the access point.

I created, based on the work of several other folks, a US ceiling mount adapter, with a 20mm relief height, and posted it on Thingiverse:

https://www.thingiverse.com/thing:2524579

This is a simple part, created in OpenSCAD, but I am inordinately proud of it, as it is the first 3D printed part that I have created, without any outside assistance.

I'll probably talk more about 3D printing, in the future.  I recently acquired a used Prusa i3 Mk2 printer, and have been highly satisfied with it.