I just want to take a mesh which is right- or left-handed and mirror it (to make it symmetrical, so ending up with two meshes).   I know the mirror function does this superficially - the mesh is visibly mirrored but the weights are still tied to the same bones. For the new mirrored mesh, you still need to delete the old bones, add the counterpart bones on the other side, and remap the weights to those matching counterparts, - but how? How do you copy the weights and transfer them