How do you use counterspell?Follow

I know how to use counterspell (i.e. click when the mob is casting), but I was wondering what the best method of targetting the mob for counterspell is. I have a [target=mouseover] macro for remove lesser curse, and a /focus macro for polymorph (well, 3 really, one is the basic and one each for party and raid notifications of who I'm sheeping, I use different macros in different settings), but I was wondering what the recommended way to use counterspell is. Is it a /mouseover, just my basic target, or should I use /focus for CS and use a different method for sheep?

in arena both my sheep key and CS key are target=focus. If we happen to be DPSing a caster on my team its up to the war/rogue to take care of that target. With sheep and CS on one healer it allows me to lock them down for a while longer. But I do keep the regular CS button close incase I do need to get one off on my target rather then my focus I can just click.