I've been keeping angels for over 30 years and currently have 12 in a 220g tank. Your situation is alittle different as you obviously already have 2 adult angels. How big are they, body the size of a half dollar, a silver dollar, or ??? How long have you had them?
Reason for the questions is this... when you already have adult angels established in a tank they see the tank as "theirs". They usually won't take to the addition of other angels and will pick on them relentlessly. You can remove the 2 originals, completely rescape and change how the tank looks, add the new angels, then add the old angels last. This works "sometimes". Or you can rehome the old angels and start with 6 babies. Angels do better with either 1, 2, or over 6. The reason for 6 or more is because at those amounts aggresssion is split up and no one fish tends to get picked on when say you have 3. With 3, you can have 2 pair up and harass the 3rd to death. You have a 60 so 6 juvies would work but as they mature and possibly pair up you may have to remove non paired angels as they are most likely to get harassed. Also be sure to have large plants like an amazon sword or two to help break the line of sight up in the tank.