In model space you'll constantly be changing the annotative scales based on your zooming. The annotative scale for labels is understood best when you create a viewport with the desired scale.
1. In your layout tab create a viewport
2. Set your desirired scale within the viewport
3. REGEN within the viewport may be needed
Create another viewport at another scale and you'll see that the labels automatically resize based on the viewport scale.
It's not pretty, but gets the point accross. And I can't possibly cover every possible scenerio in the video, just the most common. With you being a GIS guy it makes me happy that you approve.