Martin,
Thank you - that is very good data.
Just to be clear, the JSON file (containing the conference sessions) is currently a File, not a Type. I understand that if the session data were a Type, and I also stored the user selections in a Type, this would be the the preferred approach.
The primary reason for not creating a session Type is that no one wants to re-type / cut+paste all of the entries (the JSON file was exported from the SQL database). I am not aware of a method to upload data to populate a Type - is there a method (short of writing an app!)?
Best,
Scott