I've voted for 30. My reason is that for those who shoot second session, invariably we arrive at the shoots more or less at the same time as the first session shooters, hang around for hours and then try and get yourself together and go and shoot the course. As a suggestion, what about alternating the first & second session shooters around. It would be interesting to see if the loitering around before shooting the course affects the 'first session' shooters and see if it improves the scores of the seconds. IMO that would have the same effect as Ryan was saying with concentration issues. Just something different sometimes makes all the difference. Just a thought.