I purchased a silver 6S and discovered that I use basically two settings, 3 and 4. I use the red top cap (and red handle) purchased separately with the 4 plate and keep the 3 plate in the original top-cap and handle. Both are ready so no need to unscrew in the middle of a shave. I'm considering adding a blue handle and top cap for the 5 plate to give me that added efficiency when needed.
I must say that i was not convinced about the Rockwell 6S at first but now it's my go to razor(s).