Most traditional string instruments do not have finger positions marked, so I'm not sure how much help it would be to look, since that would provide only latera

Most traditional string instruments do not have finger positions marked, so I'm not sure how much help it would be to look, since that would provide only lateral guidance. For some instruments like violins and violas, the perspective is also lousy for determining finger position along the string, since you're looking down the string rather than from above. You have to develop a sense of where your fingers are based on the feel of the scroll and neck, not based on sight.