There is no known disadvantage to applying to all 65 schools that I am aware of. I have spoken to administrators at schools and they have indicated that they CANNOT see any other schools you applied to. The paper application they get sent is a personalized version with only their schools name on it. Likewise, the online portal the admissions committee uses does not list those details. After the first 7-10 applications, most of the supplementals ask the same or similar questions that require little tweaking. The most challenging aspect of applying to 20-30 schools is answering the question “why do you want to come to OUR school”. My best advise would be to start working on an excel spreadsheet and researching each school thoroughly. Even if the supplemental does not ask for it, the interviewers will. It pays to be pre-prepared!