Morgan,
Sorry for the delay. We were putting the final touches on v5.1.2 this weekend with a planned release for Wednesday, and that stopped me from investigating further.
Unfortunately, I just had time to do this, and the solution is more difficult than I was hoping. Originally, I was thinking there was simply 1 line of code to update, but there's actually a lot more to it to support the redirection method instead of the popup version. With that said, it is something we're looking to do for the v5.2 release (scheduled for around the end of October). With that release, we'd like to have an option for Facebook logins to either use popups or the redirection option.
I hope that answers your question, even if it's not specifically what you were looking for.
Thanks,
Alex