Depends what you want... it's going to vary a lot depending on subject motion, composition etc.

For quicker things, I'd use servo autofocus, with the telephoto, open it right up, and use the EV comp to 'fine tune'... What Stu says is right, but it can be tricky to get the subject 100% clear every time. Plus you're on digital, so you can see if it's going to look right with a couple of test shots!