Sparko

I always go by Jack Nicklaus' advice which is to always play the ball in the same place for every club.

Of course he also says to adjust your flight you can move it back and forth. For a higher flying shot play it a bit further forwards, for a lower flight play it back.

You will also find that playing the ball farther forward reduces any left to right action and vice versa for playing it further back. Whenever I start hitting the hook, I move the ball back in the stance to make sure I havent let it creep forwards, a big fault of mines.
D.