I always use Mono when playing Tourney and I use Half in Deathmatch. With mono I know i'm going to have my bonus which has saved me a load of times but in clans there are never 7-8 solid 2-4 characters. If I used half I could have a better chance of winning but I always rely on my bonus. I currently use Nightmare as my Mono and Nightmare and Skeelz as my half. I'm looking at a deck that can get me into the top 100 because I currently come around 250th.
If you rely on your bonus, then pick 2 clans with the same bonus so when you get a 3/1 split you still have 3 characters with the same bonus. It would be almost like playing mono, but you get the best of both clanse. For dt only very experienced dt players can do well with nightmare or skeelz, I would reccomend that pick a power or attack manipulation clan for dt. but it's up to you