my suggestion (of what I have seen work in Holacratic and non-Holacratic organizations) is to create pull instead of a push.
in a simplistic view on the world:
- with "push" you "force" a standard on the organization. every circle in the organization should have these roles. that hardly works out.
- with "pull" you allow differentiation and at the same time create accountability/ a process to surface best practices. whether there is a role that goes around circles to gather best practices or each subcircle has a representative in a best-practices circle could both work. you could even put out a "price/reward" for the circle or person that comes with the best shared best practice.
in short: with pull you create meaningful alignment. you allow circles to differentiate AND create a process that gives them incentives to align around things that have proven to work.