Jim,
I've verified the 'Repeats' options apply to the event itself, not to any reminder.
To achieve what you've asked, create a new event on the next available 2nd Saturday and, if event time is not important choose 'All Day' in the 'Date and Time' panel. In the 'Repeats' panel, select 'Event Repeats', choose 'Monthly' for the frequency and set 'Repeat Every' to '1' to mean every month. Next, choose 'Repeat by day of the week' and then, finally, choose an appropriate date for 'Ends' (or 'Never Ends' for a perpetual event).
If you wish to send reminders, that can be configured in the 'Reminders' panel towards the bottom of the event edit screen.?
Or did I misunderstand the question?
Best regards,
Matt H