1–3 people to start it. Add people once it works.

Across 65 million papers, patents and software products, small teams disrupted and large teams developed. Start new things with one to three people; add people once it works.
S Evidence: strong. Large trials or many studies, pointing the same way.
Wu, Wang & Evans 2019 (Nature).
Not medical, legal or financial advice.
In The Ecosystem every framework comes with a daily action, a room that checks in, and the full library.