I know this is an old thread - but I recently did something similar - I used a component to source the properly tagged mesh components under it’s actor’s root (traces down all of the roots’ mesh components - and uses procedural mesh to duplicate them and the hide them from sight). then as mesh sections - vertex color can be changed multiple times (this is done quite quickly by calculating each vertex color and using UpdateMeshSection to edit it. I apply a dynamic material instance to the procmesh and it paints quite quickly and is easily controllable.
just make sure you do it the right way so you don’t keep regenerating the proc-meshes - only update the sections of the procmesh when vertex color needs to be changed.
You can also use this technique to modify normals, UVs and tangents.
If anyone is interested in a walkthrough tutorial on this I can make it - just let me know there’s interest in it and I will take the time to create a demo project and walkthrough