Hi Fazi,
I cannot speak to the internal process (university or Vanier secretariat) of how scores are adjudicated. However, in preparing my application, I talked to several scholars. I found common in their advice the importance of ensuring that all the components of your application fit to form a cohesive picture of yourself based on the three main criteria: academic excellence, leadership, and research potential. Rather than focusing on which leadership activity would earn more points, I would suggest thinking about how you have demonstrated leadership (in big or small ways); how did you grow/impact others (again in big or small ways); how does that fit into the broader story of your life and work, etc. I say this because one scholar I spoke to had limited work experience and wrote about their journey as a camp counselor. They included both triumphs and failures (learning opportunities) and really created a cohesive narrative of different acts of leadership and how they have grown over time. Another had many years of work experience, but they did not just list management positions. Instead, they spoke of their evolution and resilience as a leader and how that led them to their Ph.D. journey to pursue solutions that could help resolve some of the systemic challenges they faced in their work.
I think you should go for it! The application's content can be very personal, so it may be more beneficial to reach out to one of the scholars at your university. When I was preparing my application, I spoke to three current/past scholars. Only one was willing to share their documents, and I believe it was because of our mutual network and friend. Regardless, try reaching out to the winners listed on your school's website. The worst they can say is no, but many are very generous and willing to share their experiences.
From my perspective, you cant know your chances without applying. One scholar told me that she knows of colleagues with numerous publications and seems very strong but did not even make it through the university selection process. Of course, the number of publications is contingent on many things, like the field you are in, so there is no golden number. I found their advice to be on point, as at the time of my application, I only had a co-authored book chapter and a single-authored manuscript undergoing peer review. Let's just say I have no complaints about where I ranked. Good luck!