Tailwind should be the primary move in the Specs set's last slot IMO as a last ditch effort to help its team members sweep late game. Also makes Prankster not a useless ability on Tornadus-I. If you're not taking advantage of Prankster, there's really no point in using Tonadus-I over Tornadus-T. HP Ice is not needed because Specs Hurricane will hit hard enough anyway.
I also think Focus Blast should be the primarily choice for the second moveslot over Superpower to take advantage of the Specs despite the shaky accuracy.
I'm also going to suggest making the LO attacker a separate set from Specs because the two are played differently IMO. On the LO attacker set, Superpower would become the primary second moveslot choice and Taunt would be the primary fourth moveslot choice since it can act as a wall/stall-breaker. HP Ice should probably be slashed with U-turn because Tornadus-I really needs to be using a status move of some sort to take advantage of Prankster.
PS Username: nyc_test