++ Very nice!

While reviewing your code and examples, I had a couple of thoughts:

First, I'd preferentially add extra spaces after punctuation characters if any are on the line. I think people are used to seeing a bit more space after punctuation.

Secondly, you might have a table of common contractions that you can swap in and out as needed (e.g., "It's" ==> "It is", "Doesn't" ==> "Does not", etc.) That might give you enough flex to get your circles even better.

Finally, I'm going to have to try the code out, as the aspect ratio is still a little tall & thin on my monitor. ;^)

...roboticus