Left: equivalent exposure time needed to reach the same S/N probed with the MDLF without lensing, assuming point-like sources at z = 6. Contours of iso-exposure are shown (100, 200, 1000 h equivalent integration). We note that the MDLF is equivalent to 100 h integration in blank fields already with modest magnification, μ ∼ 2.5. Right: map of the 3-sigma line flux limit adopting a velocity width of 300 km s⁻¹ and a circular aperture of diameter, based on the same assumptions as in the left panel. The color-bar indicates the log of flux values in erg s⁻¹ cm⁻², whereas the three contours correspond to the flux (flx) of 10⁻¹⁹, 5 × 10⁻²⁰, and 10⁻²⁰ erg s⁻¹ cm⁻².