2011-04-24, 03:14 PM
20% passes on average at the 5th try (0.2^-1), like it takes on average ten 10% scrolls to get one to work (0.1^-1), or two 50% scrolls (0.5^-1). So 10 scrolls per slot is the "average scenario". Worst case would be like 10-20 shields per slot.