Two clown loaches will take care of any snail problem. Clown loach will be good for a year in your tank, bofore it will outgrow it. However, with the angels tank is already stocked up to limits, they need clean water and low nitrAtes, which mean planted tanks are the best for them.
Give back some of your fish and get 2 clowns, snail problem would be gone in a week. They also are good bottom eaters, will clean tank nicely. They need a hide out cave, otherwise you will not see much of them.
Do not use copper based meds for snails. I did. I will never do that again. Stripping the tank down and starting over was the only way to get my plants grow again.