QUOTE (TheOOB @ Apr 18 2011, 06:02 PM)

The section on the book about firing two weapons is completely and totally irrelevant. Multiple spellcasting does not reference it, and visa-versa. Multiple spellcasting simple says you split the dice pool, and by definition a dice pool is all the dice you roll on a given test, including dice pool modifiers.
See the Steps of Spellcasting.
Relevant part of STEP 3.
Multiple spells may be cast with the same Complex Action, but to do so the magician must split her
Spellcasting + Magic dice pool between each target.
Note: Notice that the Pool referenced above ONLY includes Stat + Skill. This is important.
STEP 4: MAKE SPELLCASTING TEST
Casting a spell requires a Complex Action. The Spellcaster rolls Spellcasting + Magic,
modifed by foci, totem bonuses, bound spirits, and/or Visibility modifers.Note: Notice NOW, how other modifiers are now added. This is important. If they were included in Step 3 (as you declare they should be), then you would have already split these dice (as they would have been included already), which you did not do. See? Simple. Never forget,
Modifiers are always seperate from your pool, as they may not always apply. That is why they are called
Modifiers.
So, you construct your Split Dice Pool (your Magic + Spellcasting), in your example: 10 Dice (Magic 6, Spellcasting 4). For your Maximum of 4 Spells (As many splits as you have Skill), you could split 3,3,2,2.
Then add all relevant modifiers to aactually make the test. So any Specailty, foci, totem bonuses, bound spirits, and/or Visibility modifers are then added/subtracted to the newly constructed base pool. So, assuming Specialty (+2), Foci (+2) and Mentor Spirit (+2), and No visibility Modifiers because you are targeting through Astral Perception, you now have Dice pools of 9,9,8,8. with +3 Drain to all relevant castings.
Works same for Gun Bunnies. Why would there be completely different rules for the exact same actions? Simple. There would not be. I know that previous editions frowned on that design principle, as they routinely had 87 different subsystems, dependant upon what you were doing. SR4A does not take that route. It is simpler and more elegant, at least in my opinion.
Anyways...