Movie Making Manual/CUS Casting
Since we only had a limited number of people in our 'talent pool', we had to mix and match for the best match of character to actor. While this meant that sometimes the preferred act was not provided, it meant that we would be able to film without constantly reusing actors in main roles.
The general casting period was more or less finding out who would be willing and interested in joining in such an undertaking. Fortunately, the number of volunteers that were found numbered almost enough to cover all roles that were needed. It was at this period that specific characters were considered for each actor.
A side effect of casting in this way meant that most of the cast and crew would know each other. This meant that when shortlisting actors for specific characters, we could typecast into who we thought would be the most successful at portraying a character.