Comparison between fitting spectra from individual apertures vs. fitting all apertures simultaneously with shared nuclear parameters for ESO 320-G030. Left: nuclear fraction, β, measured from the simultaneous fitting on the y-axis vs. the individual spectra on the x-axis. The solid black line shows where they are equal. Right: measured optical depth of the nucleus for each aperture individually and for all apertures simultaneously. Note the much smaller error when using all the spectra simultaneously.