The thing about sunsets is that the colors are so varied and subjective that 100% true-to-life capture isn't really necessary.
Colors should be nice and rich but they don't have to be perfect. In fact, sometimes, there is such a thing as "too perfect."
Sunsets are often more concerned with mood and composition than accurate color rendition.
Any good color film should be able to do that for you.
I live on the shore of Lake Erie. I see a lot of sunsets. You can see, literally, every color of the rainbow.
Have yet to capture a green flash. Have never even come close to capturing one on film. You've probably got a better chance of winning the lottery.