The chimney people came and removed the double wall pipe from behind the wall. This is after I tore my nearly finished wall down! They extended the stainless steel t connector to connect into the double wall that runs into my stove. Now the stainless will be the only thing hidden behind the wall. Now, just to do the wall again-this time with wonderboard. Feeling better about the set-up. If anyone senses any problems I'd appreciate the tips.