but my comment appears to be stuck in "awaiting moderation" limbo, so I hoped someone here could help.
That's generally a good sign. I force all the comments on my blog to go into moderation. It takes longer for someone else to seem them, but it also means I read each one.
There was a note on the author's page regarding how to print. I wonder if that explains any of the issue you are seeing: "Flash objects can also be “printed” using the familiar Serial.print[ln] syntax, but this requires a small patch to the core Print.h file. See “Patching Print.h” below."
I did run your code and duplicated your behavior. I tried several different iterations and couldn't find something that worked.