I haven't done the classicalguitarcorner course, but seriously considered it for this summer. I am fortunate in living in a place where I have easy access to classical guitar teachers though, so instead decided to change things up by taking lessons with a different teacher. I would expect it to be useful though based on Simon Powis' other offerings. Keep us posted on how it goes if you take it!
btw I wrote a new post on short scale guitars
http://adultguitarjourney.blogspot.com/