Interesting information, Chris. I just assumed that hotplate plug would pass through vent hole. Also, if you go into the 2000 watt range on a single burner, as recommended, you have to use a hot plate wired for 220 volt. I don't think that bother would be necessary. You are only some 15 to 20 degrees shy of your highest need at 150. My GUESS (am most facile and light of foot when it comes to guessing) is that if you used a stainless pan instead of cast iron, which is now proved to be too much of a heat sink in this situation, you could get the temps you needed. At any rate, seems you are close to utilizing the Smoker as a smoker.
Also, instead of using sawdust, if you want a gentler smoke, cover the pan bottom with cross sections of a green limb, say 1/2" thick by 3/4" in diameter. They burn down slowly and you could lay in more through the side door with tongs if you need to. An alternative is to add liquid smoke to the cure, sufficient to your taste, and forego the pan altogether.