If you want an ImageWriter II to print in a condensed font, you can define that through the DIP switches. However, when you are printing using the ImageWriter II driver from a Macintosh, the configuration is overridden by the driver software.
The Macintosh might support condensed print when draft mode printing is selected in the Print dialog box. However, the application doing the printing must support condensed printing. By default, the print drivers override the switch settings and turn off the condensed mode.
To have all applications print in condensed mode, you would have to patch the print drivers at the point where they actually override the switch settings of the ImageWriter II. This is unsupported and undocumented.
The best solution is to utilize a font which is condensed in nature.