I'd just like to add this in case anyone might benefit from this thread in future application cycles.
The SF Match "Target Date" of early September is totally bogus. I honestly don't know why they even list it. It is a disservice to applicants, especially considering that a not-insignificant number of med schools don't have a lot of ophtho applicants and/or advisors who can convey good application advice. So, here's my advice.
Basically, submit as early as you can. The application opens in June. Try to submit in June or July. Ideally, you would have your letters requested by March or April to give your writers enough time. Your personal statement and CV would be finalized around that time so you can submit them with your LOR requests.
Unfortunately, because of the SF Match's early match, the way that away rotations and med school calendars are organized does NOT allow for the possibility of doing rotations early enough that you can obtain letters to submit with your application. Is it worth it to delay submission until you've received letters from 1-2 away rotations? I don't know, it's a bit of a gamble (you're assuming that your rotation will result in a letter at all), it depends on the individual applicant.
During this process, it helps to have an advisor who JUST went through the process. That can be an M4 (who just matched at the last cycle) or PGY-1 (recent grad from your med school). See if your student affairs office can put you in contact with that person. If they're willing, it helps to have someone you can text/email when little questions come up, since the Student Affairs office may be unfamiliar with the SF Match's unique considerations.