Wow, that was helpful! I get now really stable readings from the load cell with your code. The number of load cells is also ok for me--I need only one atm. Also reaction time is sufficient for my purpose.
In the meantime I found an other implementation for the ADS1231: A barkeeper robot: http://barwin.suuf.cc/ You can find the code under GitHub - rfjakob/barwin-arduino: Arduino code for the Barwin cocktail robot and the part for the ADS1231 under https://github.com/rfjakob/barwin-arduino/tree/master/lib/ads1231 . Unfortunately it is not a genuine implementation, it contains some stuff for the robot also. Perhaps it could help to improve your code or is at least interesting how other solved similar problems.
When someone needs advices how to wire an ADS1231 and Arduino have a look at this posting:
http://forum.arduino.cc/index.php?topic=198139.msg1567761#msg1567761
How you can find ADS1231's pin1 is shown on:
http://forum.arduino.cc/index.php?topic=213263