magnetic thermometer on double wall pipe?

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.

If you can place the Thermo on the stove surface the double wall pipe will not record the stack temps.

Btw Russo is out of business but parts can still be bought. If you plan on keeping the stove for a while get the parts like blowers ect that wear out. Even now parts support is limited and dwindling
http://fireplaceseast.com/06_wood_coal_stoves.htm

You can try this site,
www.condar.com

They have stovepipe probe thermometers

Thanks for that, looks like they have something that would work!