A practical test before changing hair color

I am preparing a remote consultation for a new hair-color client because the client cannot visit the salon until the day we perform an in-person strand test. I need notes that remain useful when we later compare real swatches. The difficulty is that her webcam adds warmth while the reference photographs she sent were taken under several kinds of indoor lighting. I would not treat a video frame as a precise color sample, but I would like the conversation to narrow down sensible shade families before the appointment. I found this online color analysis as a question guide rather than a substitute for physical swatches. Should the client send an unfiltered window-light photograph, and is it worth comparing the same image on two devices during the call? I also plan to document old color, regrowth, and practical constraints. How would you keep this efficient while leaving the final choice for the salon?