I'd like to try out some Giratina ideas ive had recently, but most of my time is going to be devoted to VGC. Anyways my first idea is an hone claws shadow force, shadow sneak, dragon claw set. Dragon/Ghost has amazing coverage this gen. Another idea is an offensive calm mind set with shadow ball, dragon pulse, and thunderbolt, because with those three moves you have perfect coverage and you dont really fear Ho Oh nearly as much. Arceus Rock could still phaze you, but I would recommend using something that lures and takes down Rockceus.