As identified in our previous work , TD-DFT methods without dispersion correction cannot reliably describe excimer binding. The error due to a lack of accurate inclusion of dispersion was indicated by each TD-DFT method experiencing a deviation from the reference binding energy that increased with system size. While the DFT-D type dispersion corrections tested therein generally reduced errors compared to the SCS-CC2/CBS(3,4) reference, their improvement varied somewhat significantly across systems and functionals tested. Groundstate optimised dispersion corrections appear limited in their ability to account for the potential change to the strength of dispersion forces upon electronic excitation. Nevertheless, we can consider the dispersion contribution predicted by groundstate dispersion corrections as a "lower bound" to the unknown excited-state dispersion. Using ground-state parametrised corrections at least corrects the ground-state dispersion component of the interaction energies giving a fair assessment of each functional's performance. DFT-D3(BJ) and DFT-D4 damping parameters were therefore optimised for the newly defined spin-scaled functionals to properly test their performance (details in Section 3.2).