Does Duriel/Andariel drop Mythics at a higher rate in T4 vs lower difficulties?

I’m Paragon 181 and was finally just able to take Duriel down by myself. Took approx 15 minutes with a mana shield sorc, but we did it lol. If im trying to get mythics, should I stick it out in T4 or lower the difficulty to kill him faster? What’s my best shot at getting a mythic and potentially with a GA (or 4)?

Thanks!