It took me a few tries, but I finally made expert.  Do as follows:
 
Round 1:  Wait for the 2nd group before seating.  Start picking up gifts, but wait for 2nd Derek before using confetti.  Make sure to serve Norbit and Diane first.  Norbit is a very slow eater.
 
Ring Table: Derek, Jane, Diane, Maddie, Norbit.
Flower Table: Derek #2, Al, Chloe, Kathleen, Norbit.
 
Use Champagne when serving desserts.
 
Round 2:  Serve Diane first so that you can seat Maddie next to Chloe asap.
 
Ring Table: Al, Diane, Kathleen, Chloe, Maddie.
Flower Table: Al, Jane, Derek, Al, Jane, Derek.
 
Round 3:
 
Ring Table: Maddie - as soon as Diane finishes eating seat Maddie next to Chloe.  Use Champagne when needed.