So I'm installing a thru wall durevent chimney on a new stove where one has never been before. First question is what connector s to use to connect the stove single pipe to the triple wall pipe ? What order do they go on ? The directions are not clear. Next question is since I have a brick exterior wall over my 2x4 and drywall wall ,the thru pipe has to be the 12 inch triple wall pipe. This means the thimble needs to be extended . I got a price of sheet metal of proper gauge . I'm not sure what or how to attach.