Dave,
Generally, what you find in the documentation and the tutorials (http://code.daypilot.org/) are supported scenarios.
We are discussing mainly the recurrence - and here the supported scenario is the integrated built-in recurrence, as described in the recurrence tutorial:
http://www.daypilot.org/calendar-tutorial-recurring-events/
The manually-expanded recurrence is an edge case - here the recurrence implementation is in your hands. This means be ready to implement things yourself rather than using what is included in DayPilot. You may be able to pick a minor feature or two from DayPilot to help you but there is no guarantee that all tools are available. Things I mentioned in the previous forum topic apply here:
https://forums.daypilot.org/Topic.aspx/3091/how-do-i-get-the-in-built-ui-functionality-for-editing-recu
I.e. I can give some general guidance but be warned that this is an advanced topic and you may hit a wall (in terms of development difficulty, application complexity, and DayPilot capabilities).