Hi Casey,
The core Samyama list is designed to produce a balanced purification of the subtle nervous system over the long term. So, this is the list that we use twice a day, day in, day out, like clockwork. In addition to these nine sutras, we can add the self-inquiry sutra to the list, making ten in total. We could also add the healing list sutra to the regular nine if we are taking part in the global meditations at the weekends, making ten, or eleven, depending on whether we are using the self-inquiry sutra, or not.
There are other sutras that can be added to these during our regular sitting practice sessions, and these are found in the appendix to the Samyama book by Yogani. Even with these additional sutras, they should not all be added at once. Someone may take just one of them, or just one or two of them, and experiment with them to see how they affect the overall process of inner purification taking place. Using a few of these additional sutras at one time would be a lot. So, that is a way of experimenting with additional sutras during our regular sitting practice sessions. We are always staying within the overall framework of balanced sutras.
Additional sutras can be added outside of our regular practice time, such as using Samyama with specific people’s names, or using Samyama with sutras such as “grace”, or “peace”, or “anger”, or “attachments” etc. Of course these sutras could be anything, being selected according to the intuition of the practitioner, but the overall process of inner purification will work out because the general process of purification taking place during our twice-daily sitting sessions will be a balanced one.