When the reaction depends on the presence of a very small number of activated neighbors, the density of the initial configuration is fairly critical in determining the subsequent course of evolution.
This is the reason that the density parameter is made relatively accessible to the submenu, because its variation will produce the most instructive results. Therefore it is not nice to have to jump back and forth to the main menu all the time to adjust this parameter.
Either option w (few points) or option p (low density) can be adjusted to the threshold, in either case it ought to be rather low.