That's very interesting! I actually purchased a new set of 812 end links and had to file the "side flaps" to make them fit properly (they're basicly too thick for the modern speedies). I kept the old ones so they would fit the older Speedies. I haven't given curved spring bars much thought, but sounds like a logical solution. The only downside of the 1479 bracelet is that it's a perfect fit around the wrist, but it's a very tight fit around the hand (when removing or putting on the watch). The folding clasp is perhaps a bit too small? Not sure if the other older type bracelets have the same problem.