This paper provides a brief and insightful examination of the advantages achieved by employing combined phase offsetting and power allocation mechanisms in the space-time block coded (STBC) transmission of spatial modulation schemes with cyclic structure (CSM). In order to achieve increased coding gain distances (CGDs) between transmitted code words (CWs), the power allocation mechanism is cascaded to the constellation mapping process of a STBC-CSM scheme, and the optimal power and phase weights for the conveyed information symbols, together with the phases for each CW, are searched by a heuristic algorithm based on differential evolution that yields the best CGD available for the employed CWs. The outcomes of the optimization study, which is focused on maximizing the minimum CGD between all possible CW combinations for different numbers of antennas and modulation schemes, are then used to investigate and exhibit the average enhancements in the communications reliability.