Lynnabel is it too problematic to make the Cannith Callenges CR go up to 36 or so? I am not sure if scaling will be a problem or you simply need t change some integer in the coding.
They were created for a much lower level cap. It would be nice to be able to run them at cap, or even level 26 without being punished for being over level. A person could grind out some stuff before an ER too.