font scaling - labels too small

[Peter]

I have a need for fonts on my map to scale based on the map size/resolution.
 The reason for this need is that I produce maps at 72dpi for viewing on a
computer screen and I also produce them at 288dpi for printing and when they
are produced at 288dpi, the labels are so small they are virtually
unreadable.  I see that "font scaling" is implemented for TrueType fonts,
however, I am unable to find any documentation to help me understand if this
provides the functionality I need.  If anyone can point me in the right
direction regarding the font scaling functionality or what my options are
for accomplishing this, that would be great.

Thanks,
Peter