The accuracy of the circuit was estimated using a Python script, implementing a MonteCarlo like estimation.
The following sources of errors were considered:
Accuracy of the resistors: +-0.1%
Offset voltages of the opamps: +-0.1 mV
Accuracy of the LM4040: +-0.1%
Contact resistance: 0 to 0.1 Ohm
For most of the range, the relative error is usually below 0.1%. In terms of absolute error, in most cases the error stays below 10mV. This is a sufficiently low error for my purposes.
Measurements should follow.