Hey first time poster so donīt hose me to hard if this is a common subject:

Is the catch for recovery based abilities always an item or object?

My friend is eventually planning on running a game and I had this idea for an Immortal Cowboy of sorts and I was thinking about the catch: that if people fire/attack using their off-hand that the catch bypasses the toughness(and recovery) based powers.

First off all is this "in theme" with the Dreden files(I have only gotten halfway through Fool Moon)?

And secondly is there any way to price this?  Personally I was thinking -3 as this is very common but somewhat unusual, but I have no actual experience with this game.

Thanks in advance.