You can establish default properties for character formats, and then use the based property to apply those properties to other character formats.
To specify default properties for character output formats (for example):
[Char]
help = Default character format for an inline element
category = CharacterFormats
display = inline
; Use Verdana; if not available, use another sans serif font:
font name = Verdana, sans serif
; Make the characters 10 points in size:
font size = 10pt
Character format Char is the default format for any inline element to which a format name has not been assigned. The property values listed here for Char are the default values. Unless you want to specify a different value for a particular property, you do not have to include these property settings for a character format you define.