Either way works for an orchestral date. I would save after each and every take(something you may already do
) and save a copy whenever time permits(to another drive).
If you decide to do a separate session for each piece, when the first one is done, Save As Template(uncheck the option to include media) and then do the rest based off the same template. The biggest decider in this is probably time. If someone(producer, conductor, etc) is a clock watcher, working in a single session will be faster(no time waiting for closing and opening sessions)
