Changing the size of the application normal / small in the editor pane

In the editor panel we have the Size options: with the two options normal / small in the help there is little description about this option, so I have two questions: Is it possible to use two options in one project, eg in the list view, eg Normal, and in the edit small view
Is it possible to add more values in this panel, e.g. 80%, 100%, 120% or in any other way to increase or decrease the size of the application