Should we set up one project first or go business-wide?

The two levels are different builds, and the review's ranked list usually makes the starting point obvious, because it orders the fixes by what each is costing. Where the call is genuinely open, the safer shape is to pilot on one live project: one job runs the new spine through a real month-end with someone beside its team, and what that month teaches gets built into the rollout instead of discovered on six jobs at once. A pilot keeps the risk on one job, gives the sceptics a working example inside their own business rather than a promise, and turns the rollout into copying something proved. The reverse also happens: a project set-up done well becomes the template the business one is built from. What matters is that the sequence is chosen from the review's findings rather than from appetite.