Every tool in the set from the same master pattern. If the elevation needs matched panels, every tool must be cast from the same master. Different masters, however carefully matched, will drift.
First-off on the bed with everyone present. When the production tooling is delivered, run a first-off pour with the architect and panel manufacturer present. Compare against the signed sample. Approve on the bed, not from a photograph.
Documented release regime per tool. Different reliefs sometimes need slightly different release regimes to look consistent across the elevation. Document what works on each tool so a rota-changing yard team maintains it.
Store a reference sample. Keep the approved sample panel on the shelf for the life of the programme. It's the objective reference against which any panel drift can be measured.