A friend of mine recently purchased a small cabin. The previous owner took whatever stove was in there. He want's to install a fisher baby bear. The current chimney is excellent. Good ceiling support, insulation shield, stainless steel double walled pipe and cap. However, it's 7" inside diameter. We would like to put a 6" T onto the back of the stove, a piece of 6" piece of pipe with a damper straight up into a 6 to 7 inch taper into the bottom of the chimney. Does anyone see any issues with doing that?