What were the subjects at the debate championships of Yn and Chabosh, I wonder?
It's difficult to say. Khem Val kept extensive notes, of course; but he used exactly the same argument in every debate he participated in, namely, he would fill the allotted time slot minus ten seconds with talking about how amazing Tulak Hord is, then conclude with "Agree with me or Tulak Hord will kick your *** and I will devour your essence."
Generally speaking, his cross-examination and rebuttal segments consisted of "Tulak Hord will kick your *** for claiming these stupid things."
This did earn Khem Val a name for consistency, but it means we can't infer any information whatsoever about the actual debate topics from his notes.