While the Legit Build has niche value for players hoping to export their teams into official games, the for single-player entertainment. It transforms an already stellar difficulty hack into a sandbox of endless strategy, ensuring that no two runs of Pokémon Rutile Ruby ever feel the same.
In terms of strategy, consider the following:
Use the Ferrothorn / Blissey / Swampert core outlined above, adapt your speed control via Whimsicott or Thunder Wave, and always, always carry a Ghost resist.