How do you pick the hour for natural light?

You pick the hour when the photo table gets the same light as the guest's table, almost always before service. Midday in a north-facing room fails if the plate falls into a hard shadow then. The day before, at the planned hour, see where the sun lands on the table you will use. In the sierra the call is for two o'clock, the room is already full, and the only gap is a corner with no window. You leave with the hour locked and the table assigned, so the kitchen sends the plate in that light.