Hello All: Have a newly installed Russo stove, and am running double wall pipe connected to a stainless steel liner in my masonry chimney. I am an experienced woodburner, but this is a new install in this house. I have always used a magnetic thermometer on single wall pipe in my last house, but I am wondering how effective or accurate this would be on double wall, given the airspace between the layers of pipe. How do you guys with these setups measure stack temperature.. I have always lived by the thermometer in the past, and while my stove seems to run fine, I like to be sure I have it set hot enough to avoid creosote build up. Thanks in advance.