I've filled in the ones I found if you don't use 'gather companions option.
**As of 6.0 Companions start in specific towns and stay there. *Tested at Version 1.4 without Mercenary Companions Updating for ACOK 6.2, Should be accurate (at least more so than before). This list will be updated as these preferences are known. Please, add more information and custom charts, these should only be temporary. A nice chart done by Sergio_Morozov (version 2.1)