Built it using Ender-3 with Normal extra fine settings modified to "magic number" of 0.08 mm layer height. Used PAL with head temp 200 and bed temp 60. I initially built the bells upside down (i.e., they would "catch water") to avoid building a support structure. That was a mistake and they turned out badly. I then printed them in the orientation given in the STL with a support structure underneath.
The fit is very tight, but if you angle the clock slightly and start inserting it from the bottom, it fits beautifully. It is a little bit of a chore, because of the tight fit, to get the USB connector to go through the hole, but once aligned, it fits perfectly.
The bells definitely need to be printed with really fine settings in order to look good.
I am very pleased with this design, and plan to tip the designer.