Hey,
I'm looking at update a schema for the per project, much like you can do with the UI, but using the Python API instead. The only function I am able to see that updates the schema is scheme_fieled_update, but this does it across all projects instead of just one from my testing. It would be good to add the project field, as per the schema_field_read function unless there is a way of being able to edit the schema for a single project without it.
Cheers!