if possible, for battle tower, i'd have 3 blisseys (but i'd need to think of a way to deal with any fighting pkmn i'd come across).
Back when i battle towered heaps, i used Salamence, Rhyperior, Blissey.
Sometimes i'd replace Rhyperior with something else, cant remember what though..
Thinking of making another team (for double battles) involving rhyperior (with lightning rod), gyrados, someting else, lighning rod would take all the electric attacks and gyrados is free to pwn
(as well as rhyperior).