@allan.cantos I think we're starting to beat a dead horse here, but I assume when you say "manually" you mean "graphically", since either way it's done, it's still "manual" (since Revit doesn't automatically determine where you want each grid to stop)? There's no way to avoid "doing some work manually", unless Revit gets smart enough to think for itself...
Also of note, while I'm doing the "manual" setup of Grid extents, I'm using elevations anyway (so the Grids look nice by default). BTW, we don't usually stop them EXACTLY on the Level (since that would look strange), but with an offset. Now, with this idea, we could just use ONE elevation view (instead of 2 or more), but I'd still use an elevation view at some point to VERIFY what it looked like (though maybe would do rough vertical extents while selecting them in plan, and maybe would settle on a standard offset - like 4' or 6' - to start with).