Welcome to the forum!
Glad you are here!
That's a bit of a hard one. Some imprint pretty fast and some take longer. I'd recommend a week to be safer. That may be overkill and maybe it is still not enough.
The five foot fence will not keep them in if they are motivated to leave. Any breed can clear a five foot fence if they are properly motivated. What motivates them is another question. If they come out too soon, they may leave to try to find home. Some may have a wanderlust and just like to roam. Sometimes a hen will scale a fence trying to get away from an amorous rooster. They can get real motivated if a predator (real or perceived) is around. If they see me with a feed bucket in my hand, I am their best buddy. If I carry a rake or even a camera, I am dangerous and must be avoided.
Part of it depends on the type of fence. If you have a solid top where they can perch, they will sometimes fly up there to perch and who knows which side they decide to hop down on. And once they do that and get out, they absolutely forget how to get back.
In spite of everything I've said, some people keep them in their back yard with a five foot fence with a solid top railing. They are lovable birdbrains.
When you let them out, they probably (possibly) will not go back into the coop until it gets real close to dark and bedtime. Then, if they consider the coop their home, they will go back inside to sleep. Don't expect to be able to get them back inside when you want them to go without a bit of trouble.
A couple of things I'd recommend. They are flock animals. I assume your coop is solid walls, not wire. The first time or two you let them out, consider putting one or two in a crate outsidse where they can see them. They will often hang around their buddies instead of leaving. It does not always work that way, but sometimes it does help. I think this is a common way for turkey owners to teach turkeys to hang around.
Another thing. Be consistent with this. Whenever you feed them, shake the bucket or make a specific sound that they associate with feeding. This way, you can teach them to come to you and maybe even go in the coop for food when you want them to.
It's hard to state anything for certain because they are all different. Good luck!