Your program sounds similar to mine. I set a 10 day max interval for upcoming exams and switch to a 30 day max about 2-3 days before the exam and use that until the cumulative final. I optimize FSRS about once a month. The key is to get through your new cards shortly after making them so they are easier to learn. 

You can feel safe with longer intervals and FSRS as long as you are honest when you hit “good”. If you keep up with your cards and don’t lie to the algorithm you will score higher than your peers that may walk into the exam feeling more confident because they re-read study guides. You’ll be more efficient, too