My cousin runs one that DD goes to every year. Their church is very small. They ask the families to donate WRAPPED candy and/or money. They use the money to get more candy if they don't get enough - rarely a problem. The first few years some people donated the plastic eggs as well, but now they just have the children dump the eggs & take only the candy home. (As I said, SMALL church!)
They have someone who donates marshmallow peeps wrapped in plastic wrap every year. I'd be hesitant to allow that in a larger group - or where you don't know everyone they way these people do. If they get more $$ than they need, they sometimes will put coins in some of the eggs.
They divide the children into 3 age groups: 2 - K, gr 1 - 5 & gr 6 - 9. (Some schools here have middle school & others have jr high.) Because many parents have more than one child, they have the kids take turns so you can see them all. They don't limit the number of eggs each can have, but the children (even jr hi) are good about not taking too many. They usually plan on ~30 eggs/child - if it's nasty out, though, they can come home with closer to 60 because no one shows up!
They also have eggs with stickers for special prizes. I think they usually have 3/age group - there are rarely more than 15 - 20 kids/group. Children are limited to one sticker/prize. Prizes are paid for by the $$ donated & are age appropriate: beanies, bubbles, a cute bank . . . I can't think what else.
Oh, they also allow a parent or older sibling to accompany the youngest children. So far they haven't had to restrict extra parents with video cameras.
They plan it for Palm Sunday weekend so they'll have a rain date if necessary. They'd have no where to go with them otherwise.
Good luck!