How to export graphics in “Working” style environment rather than “Printout”?

I have learned recently that Export in Mathematica uses by default the "Printout" screen style environment rather than "Working" when exporting to PDF. It sometimes results in FontSize fluctuations in the resulting PDF which are very annoying.

Try for example:

Show[First@ImportString[ExportString[Style[T, 100], "PDF"], "PDF"], 
 Prolog -> Inset[Style[T, 100], FormatType -> StandardForm]]
Show[First@ImportString[ExportString[Style[T, 100], "PDF"], "PDF"], 
 Prolog -> 
  Inset[Style[T, 100, Magnification -> .8], 
   FormatType -> StandardForm]]

You can see that the exported "T" has 80% of the size of "T" that appears in the notebook. This is how the "Printout" environment is tuned on by default.

Is there a way to force Export use the default "Working" environment?

P.S. For some reason setting a private stylesheet with Magnification->1 for the "Printout" environment does not affect Export.