Angelfish behaviour is really hit and miss, personally, I think the chances of two males coexisting long term and happily is slim, even if they don't actively try to kill each other, the stress alone can often kill the submissive one off.
By adulthood, I find few males are tolerant of each other, in smaller tanks with no décor and no territory... there might be slightly less squabbling but in a normal tank, the fighting tends to be worse and its not always obvious, a quick nip here or there can drive the opponent mad when he cant get out his corner for fear of the other turning on him.
That said, there are plenty of exceptions. I had a pair of male angels so tightly bonded that they would not except female angels in the tank, god knows I tried 6 or 7! and when separated, both males lost all colour... hung in the corner and stopped eating... they lost weight drastically until I put them back together and after a few whirling dances establishing themselves again... all was good with the world, they ate and put back on the weight and it was like nothing happened.
Cichlids have such quirky personalities!