Left: FoM ratio as a function of the prior ε_P on the MFs nuisance parameters for the intermediate shear-only scenario for different values of (mag_D,  A_tot), using all three MFs. We fix A_deep = 40 deg². Center: same as in the left panel, but with A_deep = 80 deg². Right: same as in the left panel, but with A_deep = 160 deg². In each panel, blue, magenta, purple, and red lines refer to mag_D = (25.0, 25.5, 26.0, 26.5).