After months/ years of studying i found a fool proof way, it involves a lot of potions and barley any revives.
All the pokemon in this vid are catchable (except for rotom [ you can sud any Pokemon thats lighting and can use thunder shock for this)
all tm are either bought or earned from valley
so here it is Enjoy!
after the vid cuts off all you need to do is lower meta. hp and let rotom die, then bulk up mew 2 and use calm mind.
Then use earthquake on meta, tyranitar, and psy on sloking and garchomp, then just use psy an arcues 2x and your done