The best thing to change is the dpi because that makes your fonts bigger without messing up your apps. This article is talking about how to 'optimize' font display which isn't exactly what you want. Try using these instructions instead to make your fonts larger rather than smaller (which is what 96 dpi does). Don't be afraid to jack this up to 2-300 if you need to.
If you start X with startx, edit
/usr/bin/startx and change:
If you start X with a login manager, edit the configuration file and add -dpi 120 to the ends of the
/usr/bin/X commands. Under Slackware 13.37, the files are
/etc/X11/xdm/Xservers (for xdm) and
/usr/share/config/kdm/kdmrc (for kdm). In 13.1, the file for xdm was