As for your problem, Chopin's hands aren't your hands. I can't think of a single piece that I've used the exact fingering my score gave me in every place it gave me one (which with urtext editions is often sparse in and of itself). Good fingering is a means to an end, not an end unto itself.
Right now I'm working on the Chopin etude in F minor, op. 10/9. In the LH, the first bit is an F-C (interval of a perfect fifth). This is marked to be played with 5-4. This puts unnecessary strain even on the largest hands. Perhaps it may not have been so in Chopin's day, as the keyboards were narrower, but on today's pianos it simply won't work that way.
You're right; fingering doesn't really contribute to the sound, it just makes the sound you want easier to achieve.
If you have a strong knowledge of the principles of piano fingering, you should be totally qualified to come up with something that suits your hand. Look through the scores of just about any serious piano student and you will likely find scratched out editor's fingerings and penciled-in markings that the student has discovered as being more suitable for their hands and their level of skill.Rarely will a passage have only one way to make it work.
Topic: What happens if I don't follow the fingerings? 