Would it be feasible to do a three-point palette remap where instead of doing a palette extraction from the source texture and palette texture to create an output texture, it does a palette extraction on a source texture, a "source-adjacent" texture and a palette texture to create an output texture from?
The idea was that this could be used for cases where for a given source texture there is a pair of textures of the same thing but different materials such as signs (i.e. the oak sign item texture would be the source texture, oak planks would be the "source-adjacent" texture, another plank texture would be the palette texture and the output would be a remapped sign item texture).
My assumption is that building the palette swap table from the two planks (which often look fairly similar except for their color) and then adjusting the output colors with the difference between the input sign palette and the input plank palette would produce more correct results in the details of the sign texture (i.e. the "text").

Discord conversation: https://discord.com/channels/313125603924639766/540691915373412393/1279848924903112735