Hey good question! I'd also love to hear what others think about this 🙂
I firmly believe that practice full-lengths are the most important thing, not just during the last 2.5 weeks, but especially then. Aim to take one full-length every 5-7 days (some people advocate taking more, but I think it risks becoming too exhausting, and also doesn't leave enough time to review). Then spend the next day, or preferably two, reviewing everything from that test. You can certainly focus more on missed questions, but don't neglect the ones you got correct.
With the remaining 3-5 days each week, work through passages. I see opposite extremes on this front - some people are so tired from their full-lengths that they don't end up doing many / any, while others think they need to do TONS of them and try to work through ~20 per day. Neither extreme is a good approach! You asked about content areas still being weak - this is ok, because content review should be a constant process, and nearly everyone still has weak points in the last 3 weeks or so, whether they notice it or not. You just have the advantage of knowing where your weak points lie! But this should be where the bulk of your "extra" practice passages are devoted. For example, say you know you're not strong with physics, or particularly optics. If you have access to practice passages through any reliable book, look through it for optics / light passages, and do them one at a time. When you finish a passage, if you're missing ANY questions that basically rely on content, you should go back to your notes (if you have them) and figure out exactly how you went wrong. It's also fine to go back to the actual book, though notes are preferable in the last few weeks because they're more concise. If you didn't take great notes originally, of course you'll want to look back to a prep book or even online to do this!
In the end, a more "passage-based" approach has a few advantages. The main benefit is that you only end up going back to review the content that you actually see come up in MCAT-like passage settings, instead of panicking and trying to go over every little detail related to optics. But if you don't have access to a lot of reliable passages, it's fine to adjust this 🙂
Finally, do verbal, lots of verbal, every day!
