In this case, you would need to lower the gain so that 200 grams gives code 1023.Then you could measure any change of 0.2 grams with 0 to 200 gram range.
The problem is, that when I lower the the gain the readings of the grams is too close to the drift values from the Analog sensor to get a good reading.
Make sure you apply the maximum weight you'll ever need to measure prior to setting the gain.This procedure sets the span.
what is linearisation amplifier?
I've never heard that before? So depending on the weight I have on the scale will adjust my reading when I change the gain?
I think you should try VREF5 (jumper pins 4&15) after reading