I think it's important to note the difference between "Reminders" and "Notifications".? ?In general, I find the "Add Reminder" button to be by far the most flexible method, as Shal suggested.?
Note that the "Send Invite to Group" if checked will send an iCal Invitation immediately upon posting your event.? While this can be helpful, it's also possible that you will receive a bunch of invitation acceptance notices, since it's not simply a notification, it's an Invite.? (I'm actually not sure where any such acceptance notices would go.)
On the other hand, the "Send Notice to Group when Event Happens" button will send a notice (if I understand correctly) at the time and day that the event occurs.? In our case, it's much to late to notify or even remind anyone who cares to participate.? So I generally don't see much use for this one unless someone is just down the hall and needs to be awakened to join a meeting that's just begun.
So we just do a little arithmetic and use the "Reminders" feature to send a calendar reminder at an appropriate lead time before the event, as Shal has suggested.
I do wish that there was a way to pre-set the calendar settings to a default for a group, such as automatically displaying the Week rather than the Month; having a default Reminder lead time, etc.? That was one of the good features of Yahoo - far outweighed by their constant meddling and outages!
Regards, Bill (A relatively new user/owner - just migrated our 165 member group from Yahoo last month, so still learning)
Bill Rawsky