Thanks for your replies.
Yeah - I know they all work, I was just curious as to what was the most common place. Problems arise where I might, for example, play option a and the pianist/guitaris vamps option b. If we are both really outlining the chords throught the progression, it can make things a little ill-defined.
I end up just playing some Bb scalar thing when it comes to those bars anyway

, especially when the tempo is approching the 300 mark!
Douglas.