Hi David,
in your case you should not set the field format to 'Rich Text', choose the option 'Plain Text'
Rich text is used only when the font settings defined in text modules or SO10 to be considered.
Plain text is used only when the font settings defined at the font palette to be considered.
in your case you are expecting the fonts defined at fonts palette to be considered so please try 'Plain Text'.
Regards,
Satish