>>30428089first thing is to watch this
https://www.youtube.com/watch?v=hAzabFCJtbsget a good idea of what they actually look like
As for the characteristics, to manipulate them perfectly you would need dittos that have your highest IV match the specific IV that is needed for a certain characteristic. For legendaries you can only have a variety of at max 6 characteristics because 3 of the IVs are 31. That shoehorns it into either Takes plenty of siestas, Likes to thrash about, Capable of taking hits, Mischevous, Somewhat vain and Impetuous and silly.
I'm not sure if all of them are even available since I believe there's some kind of priority on which one shows. I thought it might be Hp > ATK >DEF > SPATK > SPDEF > SPEED, but my Solgaleo is alert to sounds. I guess it might choose what shows at random? Dunno. Anyway, the idea is to have some dittos with ONE stat at a certain IV and all the others lower, the higher the one certain IV is, the better. Even though Somewhat vain is associated with 31 IVs in SPDEF . so is 26, 21, 16, 11, 6 and 1. So if any of those are the highest IV, then you get a "somewhat vain" pokemon.
Check here:
http://bulbapedia.bulbagarden.net/wiki/CharacteristicIt's actually not that hard to breed once you have the destiny knot and dittos, as the destiny knot forces the egg to have 5 randomly selected IVs from the parents. So if you have a Ditto with a characteristic you want and breed with that destiny knot. Of course, it can also select them from the other parent but so long as you have one of these IVs as the highest in every particular stat: 31, 30, 29, 28, 27, (30 dittos for every characteristic) then it should be fairly simple. Just nickname the dittos so you don't forget. Anyway, GATHERING the dittos is the actual hard part. It would take months. However, you can ask someone to hack them for you.
Anyway, that being said - you can max out the IVs later with a gold bottle cap. Thus being aesthetically perfect AND battle perfect.