We are considering buying your WordPress Carousel plugin but before we do, I need to know that you can change the thumbnail labels globally to a different font/size/colour and also how you go about writing the custom CSS, i.e. list of ids and classnames.
We don't have a list of ids and classnames. You can use Firebug https://getfirebug.com/ or Google Chrome Developer Tools to find out the id or the classname you are interested.
To change font, size and color of the thumbnail labels, you can goto Step 3, Options tab, click Skin CSS button, then change the CSS.