A sustainable weekly oncall rota can work with about 6-7 people, as you noted. To answer your question you collapse roles when appropriate. If you really only h

A sustainable weekly oncall rota can work with about 6-7 people, as you noted. To answer your question you collapse roles when appropriate. If you really only have 10 people then maybe it’s simply “primary” and “secondary/escalation” covering all the roles as needed. Get a little larger, to say 3 small teams and you might have the developrs in primary & secondary with all of the technical people managers/team leads/senior ICs in a dedicated “escalation management” rota that handles the “commander”, “scribe”, and “liason” roles. Dedicated support for those specialized roles only really makes sense when you get big enough that coordination becomes its own problem.