Specify Mesh.MeshSizeMax & Co. per Volume
I almost always get meshing issues, when I try to automatically mesh a multi body part consisted on very large and very small volumes at the same time. It would be very usefull to specify Mesh.MeshSizeMax for each single body in a multi body part.
In order to avoid collisions when two volumes share same surface, following logic could be applied: I would still define the element size for whole model and then define element sizes on single volumes. If your program sees volumes that share surfaces then only the global element size is used (the mesh size per volume is ignored in such cases)