We use a rotation that is in place, and we pair up an experienced racer, and RC person, with someone who is newer to racing, or may be a crusing sailor.
On our small lake, we can usually do RC with 2-3 people, as long as both are comfortable with operating the boats.  We use a small pontoon boat forthe RC boat and a chase boat that is fast and maneuverable to set the marks and execute rescues or assistance, if needed.  We often have some folks who come along to learn more about racing, or to take photos, and they can be helpful in scoring, etc.
We publish the schedule early in the year.  Once the schedule is published, if you need to change, it is your responsibility to find a replacement.

Neenah Nodaway Yacht Club has a committee boat (skipper, PRO, 2 assistants) and a chase boat (Skipper, assistant).  Skippers and Pros are trained volunteers who schedule themselves.  Some assistants are volunteers who like to come out every week.  But there is one assistant position which is filled by rotation from the fleet.  Each racing skipper is responsible for filling that position with him or herself, a crew member, or someone else who can lend assistance as required (setting and raising marks, adjusting anchor lead,  raising and lowering flags, noting flag numbers for finishes).    No prior experience is required, but volunteers who are afraid of water are discouraged.