Top: FoM ratio as function of the prior ε_P on the MFs nuisance parameters for different values of the limiting magnitude mag_D of the deep survey when V₁ alone is added to the shear tomography with ℓ_max = (1500, 3000, 5000) from left to right. Bottom: same as in the top panel, but for V₂ alone added to the shear. In each panel the curves for different mag_D are so superimposed that they cannot be seen at all.