Attached are two images.

To generate the levels on my drawings so that they all update when the model elevation changes, I add some text and then click on a vertical dimension on my drawing view. (I have a view outside of the extents of my title sheet that I use to grab the dimnensions.)

Next I override the units from mm to m. I then block the text with a little black triangle.

Any ideas if there is a better way to do this? Like some kind of coordinate system I could use?

I've found it's best to model my structure on the TOP plane and then offset another reference plane for the 0.000m plane. That way if the building's elevation changes then on the plane will move and my view on my title sheets will still be in the right place.