I did complete the process last night. It was a bit of a struggle every step of the way to be honest, and I'm pleased I was eventually successful, though it wasn't as easy and straightforward as I expected it to be.
I very much appreciate the effort that went into making it possible to use a Pre2 on Sprint. I also very much appreciate the help and advice I received in this thread. I sincerely hope that I'll be able to get a new webOs phone off a shelf from a service provider when the Pre 2 fails someday.