As a mage, I have a number of magical tools that I have dedicated to specific Arcana. My GM and I are wondering what if, any bonuses, may apply? I am on the softer side, thinking that the bonus if any should be based off of how relevant the tool is to the spell being cast from that arcana, as well as the quality of the tool, i.e., a ring of solid platinum-190 is a superb matter tool, but only when dealing with metals, not so great when dealing with wood or concrete, so the bonus would vary based upon what rote was used and on what, where as my GM is on the more "eh, call it plus 3 to all Matter rolls." I agree that that simplifies, but I don't want to take advantage of the system too much.
As detailed on page 124 of the Mage: the Awakening core book, the use of a magical tool removes one die from your Paradox pool where applicable when casting a spell. Adding "+3 dice to Matter rolls" would be the equivalent of a free Willpower on every spell; that's pretty powerful, but if your Storyteller wants to do it…