The eighth clash is 26/17. But what on earth they want you to do by way of finding mutually exclusive ways remains a mystery, but as has been pointed out, if the 8 cells are to be "darkened" (odd word - is that a hint?) it doesn't seem to matter. The 10-letter bloke seems an all-round good sort - unusual for his class at that time. But how he came to resolve clashes isn't told on wiki.