Borax can be added slowly to the skimmer while the pump is running, breaking up any clumps. In this small pool, I think I would do one cup at a time and see how much that raises the pH. After you add it, wait a couple of hours and then retest and redose to get it where you want it. You can add it at any time throughout the day. No specific time is better than another for Borax additions.

BTW -- in a 4400 gallon pool, each cup of 6% bleach will raise your cl by 1ppm.

Welcome to the forum. Good for you for doing your homework and reading and learning about pool care on the forum!