Call Center Prediction Model for B2B Web

Today, I am researching call center information for a business to business enterprise website that will soon be launched to an audience of 40,000 non-technical users (consumer packaged goods in the United States only).

The big question is, how do you staff a technical call center for inbound calls without any metrics about how the site will preform, no pilot and no real experience in setting up a call center?

My research on the web has pulled up some useful resources for trying to get an idea of how many calls to expect and how many agents to staff the desk with at Go Live. My objective for now is to find the right balance between cost and customer satisfaction. With the launch of the new website it is critical to ensure that visitors have a great experience and come back for a return visit (even though the site will be non-transactional).

Can anyone recommend additional resources?

Can anyone recommend a low cost out-source provider?