Probability distributions for the Einstein radius θ_E of deflectors L1 and L3, based on σ_v,los measurements shown in Fig. 3, assuming an isothermal (SIS) mass distribution and taking into account the contribution from the host cluster. For comparison, the faint distributions are obtained with the more conservative contribution from the cluster (see Sect. 3.2). For each samples from the σ_v,los probability distribution, we compute θ_E following Eq. (2). In this work we only use the Einstein radius estimate for L3 to complement lensing constraints, and only show the estimate for L1 for completeness.