Ask HN: What is the optimal iteration?

I have a powerpoint presentation Version 1 targeting industry executives. The goal is to create the most convincing presentation. I have n friends (Manny, Moe, et al.), unassociated with the project, whose advice I respect. Time is not an issue. Each of them have roughly the same role and experience in the industry, although they obviously have nuanced perspectives based on personal experience. Should I:

(A) Send Version 1 to each person independently. Incorporate each of their comments. (B) Send Version 1 to Manny; incorporate his comments, then send as Version 2 to Moe, etc.? (C) Have them all on a conference call and making changes collectively?