>>35407421Sorry if this is a late response, but honestly, just take your time. Wait get used to Mewtwo's attack and jumping animation and you can hit your curved-excellent throws time after time.
Splitting into smaller private team lobbies so you can maximise your Premier Balls.
It's also 47% catch rate per throw with curved-execellents, GRB and a gold psychic badge, so it's the easiest legendary to catch
Mew doesn't count because it's a Mythical Pokémon. 