In my Joomla Global Configuration for my website, the Session Lifetime for my site is 480 minutes. Does JoomlaGAtor automatically inherit this session lifetime value or must I go into the JoomlaGAtor module under Advanced Parameters > Session Timeout and set the session to 28,800 seconds (the 480 minutes equivalent in seconds)? If I leave Session Timeout blank does it automatically inheret the value I set on my system or does it use the Google default of 30 minutes? Thanks.

It uses the Google default so you must set it yourself if you wish to alter this. I had never thought of setting it to the Global config's so I'll bear this in mind for any future updates.