I agree with your comments how the excellent film compliments the excellent book. However, I don't think you'll be able to do an edit that reflects the book. The problem is that there are crucial scenes and subplots that were changed for the film and never filmed. These include (WARNING! POSSIBLE SPOILERS!)

- How Jack meets Tyler: in the book, they meet on a nude beach. A definite departure from the hilarious airplane scene.

- The source of the fat for the soap: in the book they steal the fat from Marla's mother's liposuction.

- The ending: the ending in the book is very surreal in which the protagonist may or may not be in a mental institution.

END SPOILERS

So yeah, I'm sure you already know this and I am curious how you plan to go around this.