I use a similar, but somewhat different technique: I set a reminder for an item in an Agenda note, and then manage it with BusyCal. It allows me to schedule long tasks (such as writing a paper) spanning through multiple days:
I’ve been doing this for many months now, and it’s very efficient. I have a problem similar to @ahnissen 's, though, because I want to check each instance done, even though the full task is not completed (therefore, I want to keep it unchecked in the originating note in the Agenda).
The technique actually worked best in the past before synchronization was fully implemented in the Agenda.
I think the desired feature would be to have an option in the “edit reminder” window to switch on/off synchronization with Reminders for the given task (perhaps located just below the calendar selection).
Why this feature is interesting? Because I can schedule when to start a long task directly from inside the Agenda. I would later do the duplications in BusyCal (e. g. when planning my week). I have even created a KM macro to make this more practical:
The workaround is nice, but it would be better to keep the link in the many instances of the tasks in BusyCal, and use it to locate the originating note in the Agenda (e. g. for marking the task done when it actually ends).