If we can do a Protocol session for someone and ask for it to be reapplied during their transition to prevent needing a Spirit Rescue, can we make routine requests for all our clients to have a protocol session repeated at regular intervals indefinitely, for example once a week?

You can have such a request, but its effectiveness will, in fact, diminish over time. As you saw intuitively, the ability to do repeat work is a function of the power of your intention when making the request. When you do a session for a single client or a group of individuals, and ask in addition for a repeat session to be done at the time of their transition, the total effort requested to be carried out on your behalf is fully supported by the intention of the moment. When the group size or the number of interventions requested exceeds your range, the benefits will diminish. So while this is an attractive notion, you cannot take on unlimited numbers of people nor ask for unlimited numbers of sessions on the behalf of clients, because you simply do not have the inherent power. This is why incremental work will be successful and must be supported by your intentions in the moment, but will not encompass many scores to thousands of sessions.