Around $560 is a great price! I bought my variety fabric constructed blazer for $1,100 last year from the NY shop. I'm 5" shorter than you but also slim and I've chosen the size 5 instead. Apparently it looks better on me when I wear it like a jacket than a blazer.
I went to the NY boutique a week ago and before I've even opened the door I could hear Guns N' Roses "Sweet Child O mine" tune coming from inside. It's become the Axl Rose costume shop. Literally. But I ended up getting a white f*ck OFF t-shirt... the accessories were very tempting but way overpriced, of course.