In our recent published works we reported that the propagation length dependence of the conversion efficiency of the Cerenkov second harmonic generation (CSHG) in planar waveguides with a nonlinear substrate follows quite strict rules depending on an actual waveguide geometry together with the wavelength of the pump radiation. Namely, simple integral expressions show that the propagation length exponent may vary continuously from zero to a quadratic dependence. In this contribution, we generally analyze the propagation length dependence of CSHG for some specific arrangements. We also study, for the first time, the effect of pump depletion together with the influence of the pump wavelength and the effective refractive index. It is shown that the length dependence can thus be described by several categories, where the conversion efficiency is - with respect to the propagation length - linearly proportional and quadratic, but also the length exponent may continuously vary from 1 to 2 (for the classical phase-matching), including the so-called Cerenkov peak region, where the length exponent is equal to 3/2.