Hi.
Small tip for gridlines' dimensions: use the 3D dimension object or if you are in AC16+, you can use the Floating Dimension object (from bimcomponents).
It is definitely not automatic, but since it is a simple object, you can show it in multiple or all your stories - a big plus for gridline dimensions if you show them in all your floor plan views.
If you edit or add gridlines, you edit the objects once for all floor plans. This has proven to be quite an effective and flexible solution. An automatic one would be nice, but I would prefer to be able to assign constraints to a dimension object (and others for that matter) than to have a specialized automatic gridline system dimension option.
Cheers!