I had the problem with the levers not returning- started a thread, and the general consensus was that the SLR brakes were meant to work as a unit- the lighter spring tension made for easier action braking, and the return spring in the levers pulled the levers back to the ready position.
http://www.bikeforums.net/classic-vi...0-content.html
I may have set them up incorrectly, however after removing the Superbe levers and putting on 600 TriColor levers- the system works fantastically.