When reconstructing various spare parts, I often had the problem of measuring the original radii fairly accurately.
So I've created a handy little tool for myself. Each leaflet has both an inner radius and an outer radius. From 3mm - 12mm there is one leaflet each. So that the tools don't get lost, I also constructed a small box in which all 10 leaflet can be kept.
The author hasn't provided the model origin yet.