I kind of went another direction that's a good idea though.
So what I found myself doing is wrapping the end of the k type thermocouple around the coil and having the tip of it (not touching the coil) end up at the center of my flat coil.
If your trying to calculate your PSL the best thing you can do is set it to 300 and get your reading. It should be the same at 500 and 700