Choice of parameter values for the simulation is not obvious. It is also difficult to correlate the parameters of such a simple model with real-word parameters. In a real etching process the important factors are temperature, pH, and time. In a computer simulation the parameters are the unit cell etching probabilities and the total number of simulation steps.

Etching time
Corresponds to the total simulation time, or the number of simulation steps.
This is the proton concentration, so this should show how often a particular unit cell is visited. pH thus also correlates with the simulation time, or steps per frame. Obviously, if you want, say 10 frames, the total simulation time also changes. Unfortunately pH also changes the relative etching probabilities of the various unit cell configurations. This correlation is not known and is one of the main subjects of the simulation study.
This parameter is expected to influence all etching probabilities.

The sum of all configuration probabilities also changes the total etching rate, i.e., the number of unit cells removed after a fixed number of tries. This total also changes during the etching process itself, not only due to the surface morphology changes (more or fewer kink sites, for example) but also due to the finite size of the simulation world.

The etching probabilities are shown later in the form of a list, for example, p(0)=0, p(1)=0.01, p(2)=1, p(3)=1, p(4)=1. This would mean that the probability of removing a completely surrounded unit cell is zero, p(0)=0. The probability of removing a unit cell from a straight step edge is low, p(1)=1. All other probabilities are equal to 1, meaning that all kink sites and isolated unit cells are always removed, whenever the Monte Carlo simulation touches them.