Hi,
First off, make sure that the none of the audio u want panned left is on the same track as those that you want panned right.
So assuming that your client wants talkie panned left and music and effects panned right :
Arrange all your talkie on consecutive tracks (lets say A1-A4)
Arrange your music and effects also on consecutive tracks (lets say (A5-A10).
Now select all your audio and hit CMD+OPT+L (there is menu option for this as well, but i can’t remember exactly where it is). This will break your stereo pairs.
Then select all the talkie clips and on the MODIFY menu, find AUDIO and choose PAN LEFT
Do the same for the music and effects but select PAN CENTER.
To check that there are no mistakes, I would suggest muting all your music and effects tracks and scrubbing through your timeline while watching the audio meters. You should not see any activity in the right channel. If you do then there is a stereo pair that you have missed. Break it the same way as above.
Check the right channel as well. You will also have to make sure that your levels are not overshooting again.
Sorry for such a long post.
Sandeep