Changing reader default properties

I've looked at the 'sticky' FAQ and tips but they do not seem to be very current, perhaps the information is there somewhere but I've been unable to find it.

I would like to:

• change default alignment for paragraphs to 'left'
• adjust line spacing a bit

Looking in /System/reader folder I see files as in the attached image.

Is it possible to edit these and achieve the results I'm looking for? Is there a 'cookbook' of things one can do there (or with other .cfg files elsewhere)?

Thanks.

Attached Thumbnails