Not sure about all the answers but there is no real concern over GI of carbs because they are mostly coming in the form of vegetables, berries, some fruit, the occasional sweet potato or potato (which would not make the bulk of your plate anyway)....all fairly low GI and not an issue.
In your initial post you mention the 30% fat is a starting point...if you raise it to primal levels you will be out of your 40/30/30 which may be why Mark is not bothered by the zone.
Eating primal is not a diet, it is a way of life.
PS
Don't forget to play!