There is no inherent text formatting for text files, they are not rich text files, which I think contain that information. The default font size is strictly depended upon the text editor that you are using. If I open up a text file not generated in IDL, and I use Sublime Text and Word Pad, the two look completely different and the sizing for both is not the same. Your best bet would be to see if there is a default setting for Word Pad.