Segment the database by personas as buyer personas are dictated by role and not by just titles. Determine the resources to create content and programs for five personas. Although data availability is abundant, it can tell what people are searching for, but it cannot understand why they are doing so.

Initiate conversations with your sales team. Companies need to indulge with an array of sellers and identify companies and contacts each salesperson thinks would be a good interview. This will help in building a list for interview requests moving forward. 

Instead of focusing on the number of personas, it important to understand which buyer personas make the most sense to invest the time, effort, and resources to develop.

Source: http://customerthink.com/how-many-b2b-buyer-personas-do-you-need/