If I may, I'd like to give you one suggestion for tenderloins, John... Since they are small, and tend to flatten-out, when you lay them on the rack, I take the two halves (most are packed 2 to a package) and tie them together with butcher twine. If you tie them about every 1 - 1.5 inches, they maintain a round shape, and cook so much more evenly. I usually mate the thin end of one with the thick end of the other (they always seem to be thicker at one end). If you choose to keep them separate, still tie them, as the round shape smokes more evenly. I put the probe in the end, between the two halves.
Let us know how it goes!