I applied to a similar about of schools and I'd echo the statement about writing fatigue. I started as early as possible and tried to prioritize prompts that were shared between schools (diversity, challenge, etc). Its hard to comment in detail about your list but it doesn't look too top heavy, in my opinion. You may consider adding some 'safer' schools depending on your field of interest. I also read a quote on here a while ago that I think is relevant - 'for MD/PhD admissions every school is a reach', so just keep that in mind and don't take it for granted.