OH HOLY GOD IT WORKED.
(The stunt I alluded to before? I read a selection from With Fate Conspire . . . complete with RP and cockney accents. One attendee with a British mother said that if she hadn’t heard me speak in my natural voice, she wouldn’t have known I was American. This is pretty much the best seal of approval I could hope for.)
(I still don’t know that I’ll try that stunt in public again, though.)