As a point of reference, Paris has around 420 Sanisettes (single-occupant self-cleaning public restrooms). Paris has about twice as many inhabitants, but half as many homeless people, so if anything Paris should need fewer public bathrooms than SF. If SF has too few now adding another 10 over the next four years won't come close to solving the problem.
[1] https://en.wikipedia.org/wiki/Sanisette