[sciurius]

This would give ultimate flexibility, but this would lead to an awful lot of settings.

Personally, I would be inclined to go for (user definable) styles, and attach a style to each song. I expect users to want most, if not all, of their songs to have the same appearance.

Then it will be a matter of time that users will ask for style settings on individual lines, even words. While lines can already be handled using directives like {textcolor}, arbitrary parts of the text can not. I'm currently working on a design to allow this in ChordPro.