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For the Tzeentch staff of change, what are the new optimal casting values? How many dice should be rolled to maximize the ratio between being able to cast the spell and conserving power dice? Not sure if anyone has calculated this before... but the army book has been around for a long time, so I guess there's at least theory..
For example, for red fire, if using one die instead of two, the chance to succeed is 44% instead of 33% without the staff vs. 86% of using two dice without the staff... so along this kind of rationale, how about for the other spells, such as blue fire, green fire, etc.
And also, can any dice be rerolled? Including the dice of other wizards in the army, and the opponent's dice? The wording isn't very clear.
I'm pretty sure its just the caster who can reroll, but you can also reroll dispel dice, so your guess is as good as mine.
Not sure about use of the Staff of Change, but for an average caster I aim for an average result at least 2 points higher than the cast value. That gives me a good chance of getting it off and a chance at an exceptionally high power level too. But the state of the battle has a great impact on this decision: what you can use your remaining dice for, how many dispel dice your foe has, and how desperate you are for that spell to go off.
As for which spells it effects, it isn't that specific, but it's safe, reasonable, and fair to only use it for your wielder's spells.
Last edited by Khorne Lord; February 26th, 2007 at 01:11. Reason: additional detail