Thirty years ago one of us introduced a central approximation according to which the regular arrays behaviors could be estimated based on those of arrays of cylindrical unit cells with the same relative surface area of their central disks for the insulating section. This work examines and validates this approximation on the basis of 3D-simulations of Brownian particles motion for inlaid or recessed electroactive disks as well as for protruding cylindrical electrodes. The approximation is perfectly adequate for predicting the behavior of realistic experimental arrays and is valid within a few percent even in extreme situations when adjacent electroactive sections are almost touching.