In some space truss applications, particularly those with large spans, the choice of a triple-layer system might prove more cast effective than the more commonly used double-layer solution. However, there are currently no clear guidelines as to which system would be more competitive for intermediate span lengths. In this paper, comparisons in terms of the weight, stiffness and number of joints and members are made between the two system types and presented in order to simplify the choice process for the designer. The comparisons are carried out using an approximate analysis technique that is explained in this paper, and checked to be reasonably accurate and suitable for the preliminary design of space trusses.