The paper presents analyses aimed at determining how the spacing between legs of a steel lattice telecommunication tower affects displacements of its top, its natural frequency, and its self-weight. The critical characteristic of the results is that they were obtained for structures optimized with respect to the load-carrying capacity of their individual components. It was assumed that levels of effort should be kept between 85% and 95%. As far as engineering practice is concerned, the key conclusion is that a larger distance between the legs has a positive impact on the self-weight of the structure. It was demonstrated that a larger leg spacing is related to a smaller self-weight of the tower and thus a smaller quantity of material required. The proposed research and calculation method makes it possible to conclude that providing a larger distance between the legs while optimizing structural members with respect to their effort (preferably by means of an automated process) results in both higher bending stiffness and lower structure self-weight required.