>>47338742Have you considered changing your order to Metagross, Starmie, Slaking in sets 7-8? Starmie can beat Metagross's counters, while Slaking could clean up after they both go down.
If you gave Metagross max Atk IVs it'll always OHKO Greta's Umbreon with Explosion, at which point Starmie should be able to beat Gengar and Breloom with Psychic (provided you EV trained its SpAtk stat)