Spatially coupled (SC) low-density parity-check (LDPC) codes are defined by bipartite graphs that are obtained by assembling prototype graphs. The combination and connection of prototype graphs are designated by specifying some parameters, and Kudekar et al. showed that BP threshold of the ensemble of SC LDPC codes agrees with MAP threshold of the ensemble of regular LDPC codes when those parameters are grown up so that the code length tends to infinity. When we design SC LDPC codes with practical code length, however, it is not clear how to set those parameters to enhance the performance of SC LDPC codes. In this paper, we provide the result of numerical experiments that suggest the dependence of error performance of SC LDPC codes over BEC on their design parameters.