no I don't think there is any thread.
I also don't think there is any ideal formula. It all depends on the ticketprice for each seat, the league you are in, and the wins and losses you have with your team.
I think basically it is a good practice to expand the seats you (nearly) sell out on regular basis, or if you do not imediatly have the money for expansion, you could raise the ticketprice for them.
They are not your friends; they dispise you. I am the only one you can count on. Trust me.