Agree with everyone else about a balanced list, but also have a non-audition safety that your S would actually want to attend! No auditioned program is a safety, even if it’s one that is seen as “easier” to get in. Every year there are stories of people who have been accepted at traditionally more difficult schools and not accepted by the “easier” ones. Also, if you can schedule some fall auditions with schools that have rolling admissions, if he doesn’t have good results, he can always add schools. And then there are also walk-ins at Unifieds. Overall, 16 schools should be plenty if the list is balanced.
And agree 1000% about how schools look on paper vs. your child’s experience. Both of my Ds had schools on their lists that were in their top 3 that they took off completely after auditioning. Both of the schools are great programs with students who love them, they just weren’t the right places for my Ds. What your S will like/dislike will be completely individual for him.