To add, as a tank, I only mark one mob at a time.
I mark the one I'm pulling, then when its' health is very low, I start attacking the next mob. When the original mob dies, I simply hit my mark macro for the current mob, then rinse and repeat.
I felt that I didn't need to mark three mobs before the initial pull, and don't need to mark 2 and 3 during the battle.
One macro for one mark, then we're good to go.
