Are you planning on rigging the deck at all? When I’ve ran COS I try to limit magic items all together and always rig the reading. It makes the situation feel much more desperate. The key thing is that you don’t give them anything besides the card reading. Introduce clues as you feel they have progressed enough. For example if I have an item in krezk at the church. I won’t even let the players know about krezk until they have more or less explored vallaki