Typography in Twenty Twelve

I would love to have Twenty Twelve-typography customisations explained, I for example want to use Typekit but as a novice dev I have a hard time to figure out how to work with typography correctly when this theme preloads Open Sans. I get by but it feels like i’m missing out and messing up the code.

If someone put up a “Typography in Twenty Twelve post” explaining how-to work with typography and Twenty Twelve correctly I think it would help a whole lot of people since this is “the new standard”.

I do have a hard time grasping the idea of integrating a custom-font into the standard-theme since there are lots of great plugins that enable Google fonts for those who want to use them but just as many might prefer Cufon or Typekit etc.

A standard theme should be about simplicity and clean code for easy customisation and child-theme development. To rapidly be able to deploy sites built upon core-code. All in all Twenty Twelve does the job but this Google font thingy is, atleast for me, truly mindboggling.

So the question in short is: How does a novice disable Open Sans from loading and get back to work with typography in CSS like we’re used to.