Originally Posted by charleski
An important thing to remember is that while all readers will allow the font size to be increased, few (if any) allow it to be decreased, so the base font size is the minimum size that will be used.
In the Cybooks you can use smaller font sizes. I set font sizes lower than 100% for things like smallprint, superscripts, captions... and they appear smaller in the Cybook. Maybe, if I set the base font size to the smallest possible that won't be the case, but I always use the 3rd smallest size at least