Where do I put the magnetic thermometer on a Buck Stove model 85 with a blower? It is a SS liner and an insert, so on the flue is pretty difficult. Stovetop? Cast iron collar on the top of the stove that the SS insert goes into? Is there a difference in "good" temperatures depending on placement, eg add 100* to stovetop temps for actual temp or minus 100* from the cast iron collar?