Pick one cycle. Not a platform.
One control-testing cycle, end to end, in one domain. Everything after this reuses it.
- Choose the cycle with the highest evidence volume and the lowest political heat — access reviews or change management, usually.
- Write down what the cycle costs you today in analyst-days. That number is your entire business case; you will never have a cleaner baseline.
- Define done as: this quarter's cycle completes with machine-collected evidence and a human signature.
Why not start broad?
Breadth is what kills these programmes. Six half-automated cycles produce no defensible assurance and no credible number; one complete cycle produces both, and it is the artifact you take to the board for funding.