IMAXGirl

I'm doing a project for my film theory class on John Williams and I was wondering if anyone might be interested in offering some input.  The basic idea behind my project is to examine (some of) the scores that Williams has composed for different directors--most likely Spielberg and Stone--and compare and contrast these scores and ask the ask question of how and why they are different.  Why does he compose one way for Spielberg pictures and another way for Stone?  Or what is the significance of this difference.
Anyone have any thoughts?  I know this is kind of out there, but I figured this would be the best place to find people who might be able to speak intelligently on the subject.  Any ideas you can provide would be greatly appreciated!