From my experience as hub leader of the Aurelian board for a couple of years, I would suggest 4 or 5 hub leaders.
Get these guys basically on the same page 'rule wise'.
It really does take that many considering the number of messages, and the fact you have bodily functions to attend to.
With this many strong personalities and great input by all, from time to time you'll need to focus everyone, or settle the gang down.
You'll never make everyone happy, but try for a good sized majority.
If you treat all with respect, you tend to get it back.
I wouldn't trade my experiences on the ARU board for anything. I met a lot of great people, many that I am still in touch with.
I'm an NOT shareholder, and this board brings back fond memories.
GLTA. Sail on.
safeharbour