I came across a video (not Tormek related) on a cheap and easy way to sharpen serrated knives. I have an older serrated bread knife that is used at least daily and often more than that. Over the years I have noticed it's performance on sourdough bread worsening. I tried the method shown in this video and based on my sample of one it worked remarkably well. My serrations are scallop shaped. I would be interested to hear your experience using this method if you try it.
https://www.youtube.com/watch?v=4jfpij6MvpY