I bought a Center 301 (2 probe model), which I've since only had lying around. It came with two TCs without any metal tubing. (I guess that your meter came with at least two of these TCs too.) I did use that TC for that very purpose once when I wanted to know the exhaust temp inside the exhaust bowl. The temp wasn't that high, I think it was between 60 and 80C. I just opened up a bolt (between the fan and the bowl) and slid in the TC so that it was in the middle of the bowl. Then I loosely tightened the bolt again. There was no signs of the temp being too high for the TC's insulation. If you are worried about any leakage or about squeezing the TC cable, use some soft gasket material between the fan and the bowl.