Welcome to the forum.
San Fransico is a good city for tea. I was actually there last summer, and I mangaged to visit two places. In the Ferry building which is a culinary delight, there is Imperial Tea court. But my favorite which is inside China town is Red Blossom Tea, they have incredibly friendly and helpful staff, and are happy to assist you with your choices in tea.
Both of these places have websiteshttp://www.redblossomtea.comhttps://www.imperialtea.com/
Hopefully this will help you decide.