Weighted average of the full in-transit spectra in the star rest frame for WASP-69b (left panel) and GJ3470b (right panel) centred on the Hα line. Light colours indicate the not binned transmission spectra, while dots show the transmission spectra binned 20 × (in RV). The overplotted fit is performed on the not-binned spectra and represents the model favourite by the BIC test.