But yeah, if I were you, feeding off of Tolak's thinking, I'd go with about 5 angels, and a lot of tall plants, aka lots of hiding, and make sure all the angels are bought at the sametime so territories are not set-up, and the new guy gets picked on. and if adding 5 angels at once, make sure your tank is very stable and cycled.
EDIT:::: Also, it wouldnt be a bad idea to get angels of the same size.