Rok, the definition of "West Coast" jazz is very elusive. That's because the same musicians also played East Coast, as well as "No Coast" jazz. It's kind of like "bouillabaise", you have to try a spoonful. No description can be quite appropriate, and to further complicate the matter, it had a short life span. Fortunately, there's a lot on "You tube", and Amazon has it, which means it's still available. I'll post the best examples I can find so that everyone will be able to recognize "West Coast".
Frogman, since you're an aficionado of West Coast jazz, I would appreciate it if you posted your best examples of West Coast.
Enjoy the music.