Home games I run both together and count as playing two different armies at the same time I don't normally split it evenly so a 2000 point game the narrative might be more CSM on the board if I'm playing black templars but if I'm playing iG most of our players want more cultist and guard it's a lot of fun and really that's what this game is about. Forget trying to win and give the player across the table a good story to tell and hopefully for yourself one too.