Results from the radiation-hydrodynamics calculations for models differing in R_CSM. Top: Bolometric luminosity recorded at the outer boundary and starting when the power exceeds 10⁴¹ erg s⁻¹. Middle: Same as top for the cumulative bolometric luminosity. Here, we use the HERACLES time modified for the light-travel time to the outer boundary. Bottom: Evolution of the velocity at the location in the unshocked CSM where the electron-scattering optical depth is 0.01. When that location is shocked, we report the velocity at the radius immediately exterior to the shock.