I've been working on this guys Wobuffet for alittle while, so I have not yet gotten to it, but I'm almost done with the Wobuffet. Your Larvitar won't take as long though, so don't worry.
You couldn't have picked better. Tyrantitar already has great attack and defense. Tyrantitar is also very good with Special attacks like Ice beam, and flamethrower, making it perfect for assaulting weakness's