Let's set the scenario: My Garchomp uses Devastating Drake on the first turn of a Double Battle, then my Oranguru uses Instruct on Garchomp. Will Garchomp use Devastating Drake again, will Garchomp just use the original move (eg. Dragon Claw), or will it just fail? To put it simply: does Instruct work with Z-Moves? I could never get my head around it, and I don't have the games so I can't experiment it myself. Any help is much appreciated! :)
No, if you use instruct after a Z-Move it fails.