This Week

Put your current engineers against the five rungs. Not to demote anyone—to understand where the gaps in judgment actually are. You will find Builders being paid like Architects. You will find Multipliers treated like Builders.
Ask every manager what "senior" means on their team right now. If they can answer without mentioning years of experience or sprint velocity, excellent. If they cannot, that is where your work starts.
Implement one judgment-based interview question. For every candidate, ask: "Here is a piece of generated code. What could make it fail in production?" The quality of their answer reveals more than any coding exercise.
Run the vacation test on one engineer. Observe whether the team makes worse decisions without them. Document what you learn.
Write one rung of your ladder. Do not wait for perfection. A written ladder that is seventy percent right is infinitely more useful than a perfect ladder that exists only in your head.