Tipster Andrew Maser gives us specific variable settings In AutoCAD to maintain linetype scales in various viewports.
"When using multiple scales in multiple viewports, it is possible to maintain linetype scales so predefined linteypes look the same, regardless of the different scales. In the model tab, set the variable MSLTScale to 1 (this can be set up as default value, in a template file). Set the LTScale variable to 1 (this can also be set up as default in a template file). In each layout tab, set the variable PSLTScale to 1 (this can be set up in a template file). This will allow all custom linetypes to maintain size and spacing, even at different scales.
"For example: With a 20-scale drawing, my sanitary line will have a symbol every inch (on paper). If I print a section of the drawing at 10-scale, the spacing of the symbols becomes 2 inches, and the symbols are twice as big. By setting the variables as described above, the sanitary lines in both viewports will be 1 inch, and the symbols will be the same size."
Notes from Cadalyst Tip Patrol: A long time ago, before paper space, AutoCAD users (including myself) had to set the LTScale system variable to fit the scale of our drawing. This had to be done so that a dashed linetype would be dashed.
Now, thanks to paper space, you don't have to do that; just set everything mentioned above to 1 and AutoCAD will scale it for you. Draw your linework in model space, then annotate your drawing in paper space. AutoCAD will scale your linetypes to fit the scale of the viewport. Why do it yourself when you don't have to?