Hello, I am wondering if anybody can help me with this. I am going to adapt this pipe down to six inches for my new stove. The guy at the stove shop thought these pictures looked strange and has never seen a chimney like this before. I am not sure if this should all be taken out or if I can just step down to six and keep the existing chimney. The celing is vaulted. Please take a look at the pics and tell me what I am dealing with thanks.