It is impossible to say how many cards a day you should use to study for the MCAT. Currently, no study answers this question. However, you can create all the possible cards you need to memorize and trace your steps back from that. For instance, you could study for a day and estimate how you feel about that load because ability varies from individual to individual. Furthermore, everyone has different circumstances. Therefore, no one answer fits all.
Alternatively, you could calculate how many hours per day you can commit to studying and adjust your load for that. In any case, you might want to play around with the default settings. Find out for yourself how many cards you should remember in a day.
You can read more about these card review settings here. Alternatively, you could check out our Anki command shortcuts, or read all our anki posts here.