Declination rate during the plateau (s₂) measured from the synthetic bolometric LCs as a function of explosion energy. The physical parameters not being varied are presented in each subplot together with their fixed values. Each subplot shows the influence of the other physical parameters: M_Ni (left panel), M_ZAMS (middle panel), and ⁵⁶Ni mixing (right panel). Only models with optd values smaller than 160 days are analysed. Black dots represent the observations from the CSP-I SN II sample. Some observations fall outside the range of the model parameters due to the fixed physical parameters. Changes in the fixed values represent different ranges of model parameters.