Summary of the weight extraction process. The first two rows illustrate the weight construction for Fe I. Top panel: Line list of neutral iron used for cross-correlation. The wavelength ranges of the HARPS-N and CARMENES visible are plotted in boxes to illustrate the difference in wavelength coverage. Bottom panel: 1D cross-correlation functions for the four nights of observations. The two HARPS-N nights have much higher SNR and contain less background noise, producing larger weights than the CARMENES observations. The second two rows demonstrate the weight constructions for Na I. Top panel: Line list for neutral sodium. The proportion of flux obtained by both spectrographs is comparable to each other, therefore data quality dominates the weight calculation when combined. Bottom panel: Cross-correlation functions for each night, CARMENES nights obtain a higher proportion in the calculation of weights.