Maximal vertex count per part

We are Reconstruction in Normal Detail which is generating 230 parts and we have set at 10M vertex counts per part and have results with 400-600M triangles.

Is there a test to help figure out what to set the vertex counts per part to achieve the detail that you need for the project?  It looks like another 6-8 hours on a AMD system with 64 cores, 512GB ECC RAM