Have you beat the game yet and made it to the Battle Resort? If so, talk to the Ace Trainer in the Pokémon Center, he'll tell you what IVs are good, just count them. Also you will need a 6iv Ditto. Plus you don't have to evolve all of them. Once you find out which Riolu is 6 iv then evolve. Another tip is, if you have a 3iv Lucario, breed till you get a 4iv, breed the 4iv till you get a 5iv and then breed the 5iv till you get a 6iv. Also, I'd put Destiny Knot on the Ditto.