Hi, neosyberalex
If you want to add extra space between paragraphs, you need only to add (change) margin-botttom property of a <p> tag in *.css file.
To automatically make this change as a default for the program you would have to decompress the plugin, and change this property in a default.css file, compress files back and install plugin again.
This plugin runs only on one ebook at a time. Maybe there is a plugin, that runs other plugins in a loop for a chosen books - i don't know.