Fun puzzle! Or rather it would've been because I got the logic down with my first idea, got the right combo but then failed to parse it and subsequently turned it into a frustrating experience lol. Here are some other eight letter combinations that I tried after my first and apparently very successful attempt: HDDXBIKH, CALKHORN, KBYCOLNR, KOLKOTNR, BALSOETA, OLRUQSOO... I don't remember how I got at least half of these lol.