I've made a setup to efficiently "farm" Pokémon in the Virtual Console releases of Pokémon Red/Blue, with the aim of transferring over to Pokémon Sun/Moon. To anticipate future updates of the guide, the guide will be on this pastebin
However, there are some issues with the guide. As explained in the guide at the top, some of the techniques and terminology aren't fully explained, and some edge cases aren't properly explained either (such as required items appearing in the trainer ID slot). If there are any uncertainties/confusing parts with the guide, please feel free to respond in this thread so I can fix it.