Interesting... the LBS thought a spacer wasn't needed on the 11x32 because it was built-in but as you've shown, it apparently is required on the 11x34 to take up the space created by the concavity, assuming the CS-HG700 11-speed cassette is designed the same as the 8000. From a pic of the spoke side of the cluster it doesn't look concave but it does look recessed but, with the spacer already in place to bring it back to level....