I think 750 published pieces in the last three years, backed by however-many consecutive weeks of hitting my writing quota suggests that my bona-fides as a writing coach are pretty solid. I assert I know some stuff about overcoming blocks.
(Of course, it isn't exactly for me to say, is it?)
But how much does my authority expand once I've actually written a book? I mean, let's face it, even in the age of the Internet, writing a book is most writers' real goal. Right now I can demonstrate that I know how to deal with blocks. In the very near future, I'll be able to demonstrate that I know how to see a major project through.
This process portends good things.