Sorry, I didn't know the 6700 was a change over what I currently use (2000ish Ultegra tandem cranks of unknown numerology).

As for the Vectors, they were an option, but being blind I couldn't get my head unit through the calibration process every time I sneeze on the units. Plus, while Garmin swears up and down that you can't strike when your pilot enters a corner inside pedal down, they won't warranty the repairs when your pilot starts pedaling on the upside of a curb while you are still on the down side (shoud have opted for the set of wheels I wanted).

Thanks for your input.