Regarding simply quoting a lump-sum, per-photo rate, how would you address circumstances beyond your control that require you to spend more time on a project that anticipated, such as weather and travel delays? It would seem to me that you have to put a value on your time for such circumstances. I will account for these things in one way or another, or, for that matter, for anything else that requires me to spend more time on shooting than I feel I need to get the job done, such as a client wanting to spend more time on the shooting than I feel I need.