Thanks for taking the time to explain Jeff.
I'm thinking that there may be 2 export options for our needs...
(For a private viewing in our studio)
Check 'use previews' and un-check 'max render'. H.264 with a avg data rate of 7 and max of 7.
(For final delivery to client)
Un-check 'use previews' and check 'max render' as we often scale the film.
Out of curiosity, wow long does your PC take to export a 10 minute timeline with heavy color grading on it ? I'm referring to Magic Bullet.