Two points:

1) web usability: as user you don't want to be asked more things than strictily necessary to perform a task or obtain something at a given point.

CB has been designed for not too long registration forms and for unlimited user profile editing, with tabs.

So you may want to consider if possible, breaking the infos required from your users in 2
- minimum at registration time
- rest in user profile (can make it mandatory there, so user must fill out all mandatory fields before being able to save profile)

It will only increase the success of your website.

CB does not provide multipage registrations out of the box, you need to code...