The absolute minimum requirement for Emotion Code Certification is to do one session each on 30 people, and completely clear the Heart-Wall from four different individuals. However, most people find–like you are finding–that it takes more than just one session to get the best results, often times. We do need to see EACH heart wall session for the clients you are using as your four heart wall clients.
As for the other clients, you can add more than one session to your binder if you would like to, and that will show us that you are serious about getting results. However, it is not necessary to add more than one for these clients.
You will need to work on 30 different individuals. Each initial session with your clients will count as one of the thirty, and for some clients you will add more than one session. But the key here is to find 30 different clients to work with.