I used Nuka Cola Clock by techoutreach for the cap shape but scaled it down and made the hollow in the back conical so its heavier. It'll still accommodate a clock mechanism 65x65x20 or smaller, but there's no hole in the back for mounting.
Red to 24mm
Orange to 25.3mm
Black to END
Source items are here if anyone wants to make changes:
The cap is separate from the logo so it would be easy to put something different on top.