There is one rule in our finishing shop that has nothing to do with skill and everything to do with planning: the gold for a whole commission is mixed and prepared in one batch, before any piece is started.
Metallic finishes are the least forgiving materials for batch variation. Two batches made from the same materials to the same recipe, weeks apart, will differ slightly in warmth - not enough to see side by side on a swatch, and absolutely enough to see when one chair stands next to another under a dining room light. It is the sort of difference nobody can point to and everybody notices.
So the quantity for the entire set is calculated at the start - table, all the chairs, and a deliberate surplus - and prepared together. The surplus matters as much as the calculation: it covers a repair, a re-do, and the chair somebody wants added in three years, and it is stored against your order rather than used on the next job.
The same discipline applies to the ivory ground. It is mixed once for the whole set.
It means a set cannot be started until we know exactly how many pieces it contains. That is why the chair count is one of the first questions we ask, and it is not an administrative one.