I had a 125g tank with play sand from home depot, several HUGE amazon swords, some anacharis, wisteria (floating) and some giant baby tears (also floating). I had 5-6 pieces of driftwood in the tank (helped lower the pH and make it more "blackwater"-ish). I had anywhere from 2-8 angels at a time flourishing in the tank, with at least one pair breeding and laying eggs constantly. At one time I had 2 pairs lay eggs, and a third pair was trying to lay eggs but couldn't get a safe spot to do it.
I also had a driftwood cave and clay pot cave, but neither was used by the angels.
They always laid eggs either on the leaves of an amazon sword plant, or the black plastic overflows in the back of the tank.
Flow in the tank was about 1,500gph.