Hi
I have a venturer from combat companion in my party. He cast one of his spells, fluid combat (+15 OB and DB), and then the magician wanted to cast a blur on him as well. Would you let the venturer get the full effect of both spells? We ruled that they don't stack, but one spell makes his moves really fluid and the other makes it harder to hit him because of the way he appears to the eye. The only reason not to let them stack is because DB spells don't stack.