Regarding the grid questions, I don't think it was as much a question about object symmetry but more of how to set it up to build objects to scale...explanations of subdivisions, grid lines, etc....effective use of the grid. For example, if you were building an architectural model and wanted to model the pieces to scale with blueprints, then what would be the best way to set the grid up?
"Terminat Bora Diem, Terminal Auctor opus."