A couple things to keep in mind.
1. Some parents may get frustrated after a while and start eating the fry. I've seen this happen even after the fry were quite large -- pea-sized or slightly larger. I think it really depends a lot on your pairs' tolerance to their fry. Some angels seem to do really well with fry-rearing... others, well, not so much. If they get ready to spawn again they may turn on the other fry.
2. Angel fry in large numbers can damage parents as they get older. If the babies are hungry, they will actually start eating their parents. Al can confirm that
I've had mine start eating the fins off of my pairs.
I usually can keep angel fry with the parents until they are pea-sized. Once their little dorsal and anal fins start developing, I'd say remove the parents just to be safe. That's if the pair tolerates them up to that point, that is.
If you don't want the pairs to spawn, you may need to separate them. I tried a divider and they just spawned at the divider.
Some angel breeders have community tanks where the pairs go to rest, but depending on the attitude of your pairs, that may not work either. I've got some female angels that are set on killing each other, whether they're in spawning mode or not.