HI there,
Great question. I hope this answer does not arrive too late to be useful for you. It is true that many schools have not stated how heavily they weight the CASPer materials. Because Snapshot and Duet are so new, many schools are not making them mandatory yet, but again, this is often not disclosed. The bottom line is that you may as well prepare to do your best.
Snapshot is very much like a shortened interview. They can ask questions such as "tell me about yourself", or "why are you interested in medicine?", or "tell me a time when X (insert challenge or mistake or anything else)". For the first two questions (or similar ones) we recommend choosing 2-3 experiences that will showcase the core qualities schools look for. Going into depth in these experiences to showcase what you did, what you learned, and how you will carry this forward into your career will help to show the interviewer who you are and your potential. It is best not to list off too many different things that are unrelated to medicine or to certain soft skills you want to highlight. The schools will have your activities sketch, so there is no need to say everything you have ever done.
The third type of question requires some critical reflection. Like the first two, it is best to state your role in the experience, what you did to overcome it (if it was negative), what you learned from it, and how you will take this lesson forwards into the program and your career more widely. It is best to try to turn a negative question into a positive learning experience (but always take accountability for your past transgressions).
And Duet tries to match students to the programs. Therefore, you may want to look into the schools' mission statements where you are applying and ensure to be aligned with these goals and values. You should be honest, however, in what you prioritize, so that you can be fit well with the institution.
Best of luck!