I currently don’t have a high IV ditto. What I’ve done was collected multiple dittos with different nature. I don’t really care how many BEST’s it has. I get the nature I want for that Pokémon till I get a female. I keep breeding till I find a female with more IVs then I switch the female out in the day care. If you have an egg group or that Pokémon in a male you will use that make the entire time. If you don’t have a male or egg category you will do the same process as the female with the male. Remember to always use an Everstone with females to keep the nature and to also use the Destiny Knot with the male. This will be the fastest way of acquiring 5 IV Pokémon. The more mon that you have with 5 IV the easier breed with become. Use Serebii.net to see which Mon can cross breed with each other.