I don't see any gaps in the preview so I think my bodging should work fine.
Capacity is untested until my test print finishes.
Included files:
A 3mf project file of all parts from the original model with mine modifications as a separate part. The canonical version of my model is contained within,
An STL that does not include the catch notch due to Orca Slicer not exporting changes from negative parts into a single STL.