Relative errors of the 34 free parameters (left) and of the magnification factors at the model-predicted positions of the point-like multiple images (right) from the five different models (indicated by different colors and symbols). For the definition of the individual model parameters, see Sects. 2.1 and S24. While the 106 multiple images are, for simplicity, not labeled, we highlight those belonging to the SN and its host (and thus excluded in models Ewo and Swo; white background), those with variable redshift (since no spectroscopic redshift is known; light gray), those belonging to the northern galaxy group (see Fig. 2 of S24; medium gray), and those from additional sources in the cluster core (dark gray). We observe a significant reduction in the statistical uncertainties of the model parameters (left) and magnifications (right) when we include the 77 000 HST pixels as direct constraints in the strong lensing model.