The mounting system that was used in the model I remixed worked pretty well except for two key issues:
This remix is my designed mount, and the aperture modification (no other changes were made to the original model).
For the rail mount you will want the “Pin” model found here: https://www.printables.com/model/370389-sovol-sv06-enhanced-tool-holder/files
Update: as pointed out in the comments I did not link the Pi case itself. It is available here: https://www.thingiverse.com/thing:5919343
The author remixed this model.