Sith Assassin helps greatly with TM manipulation but Sith Trooper is a good tank and none of the other Sith you have are Tanks (Vader doesn't really count). How fast are your Sith? You ideally want SA to go first (and she will unless modded poorly) followed by EP, Vader then Zaul (Zeta'd Maul). Sidious would be a good fit in here in place of Nihilus with his Expose on Special attack (Omega'd) and should be slowed enough to come after Vader but before Zaul (Zaul's AOE then could presumably kill half the enemy).
