I think it is possible to add the mod to the cms
you just need to find some code (like I used <blockquote>) that is uniquely wrapped around the text you want to change size.
And then you need to create a copy of the js and replace the blockquote code with the one you found/want to use.
Then include the new js as well in the header.
Unfortunately I don't use the CMS so I can't adapt it for you.
The text-to-speech is a licensed service from ReadSpeaker.com.
I pay a lot of money for that with annual fees.
However the implementation of ReadSpeaker Enterprise into vbulletin currently
only works with a product I got written for my forum.
I am currently in a negotiation with the company about if they want to acquire the plugin.
But if you think about acquiring a readspeaker enterprise license, send me a PM