Customer support for every company is going to be different; there just isn't a formula. Some companies can utilize more automation because the types of questions fielded are going to be very similar (e.g. "where's my package?" or "how come there's a flashing red light?"). A team of 8 just about anywhere can scale to fairly high volumes.

But since we're talking about the Bay Area, and it sounds like specifically for a technically focused company (I'm thinking startup) the good news is that the core team is likely already fielding support because talking to customers is so important to the growth and direction of the product. Yes Bay Area salaries are high, but hopefully you're hiring high quality team members that are more than just front-line support -- they should be an invaluable part of your product and customer development process. You can't really put an outsourcing price tag on that.

Lots of companies have a process where the developers are insulated from day-to-day support roles -- and if that's working, great. But, the best companies have developers who want to talk directly to (or at least have support access to) customers and understand their problems first hand. This is where the high salaries more than pay for themselves.