the intensity OEis whose eigenvalues are within a chosen fraction of total intensity. This is equivalent to considering only beams that have a significant intensity contribution in the ROI. Intuitively, the optimization procedure may perform so well that a spot of size zero is finally obtained if no intensity threshold is applied. Figure \[fig3\] shows the smallest spot superposition where we observe the appearance of sidebands just outside the ROI. These sidebands are a secondary effect of squeezing the light below its diffraction limit. It is these sidebands that decrease the efficiency of the squeezed spot with respect to the maximal possible intensity in the ROI as calculated via the IO. Using the ratio between these two intensities we can define the intensity Strehl ratio [@Sales:1997p9891] for the SSO (see Fig. \[fig4\]b). We remark that both, the spot size and the Strehl ratio, show resonances as a function of the ROI size. This can be explained by considering the number of intensity eigenmodes used for the spot size operator. Indeed, as the ROI size decreases, so does the number of significant intensity eigenmodes. Each time one of these modes disappears (step in Fig. \[fig4\]), we have a sudden increase in 