For my current setup, the most efficient way is to use larger models for coordination, but a heretic'ed qwen 30B model for the implementations. If you build your agentic environment around specifications and test coverage tied to symbols, you can do a lot of parallelization of agent work.
If you then separate the filesystem and tool read/write access by agent roles and policies (e.g. coder not allowed to modify unit tests, tester not allowed to modify code files) then you can force them to use a centralized per symbol/per contract specification tool.
And then you can just let agents discuss issues, where the messaging threads are also tied to the same symbols.
[1] Exocomp, highly experimental: https://github.com/cookiengineer/exocomp