We do our grading plans using a modelspace viewport with the title block and annotation in paperspace. The viewport, especially irregular shaped ones, allow saving extra blank space for notes and details. They also allow easy adjusment of the area displayed should the project be split into different phases. Also there are times when the projects can fit on a more useable scale if they are rotated and we find a rotated view in paperspace to be a very easy solution. We will usually xref our base sheet for the grading and drainage plans if they are a large multiphase project. In this case we place what annotations and linework only needed for these plans over the xref in modelspace. For smaller projects we will sometimes just make a tab for them in the base plan.