I've seen anywhere from 3 days to a month. I believe 10 days is just about perfect. By far the most important thing to do is to follow through with your tree. In a sense, you are guaranteeing everyone a copy who signs up for your tree. You want to try and make sure everyone gets theirs.
Trees can be successful but communication is key.
Sometimes, parents fail to contact their children if no progress is being made above them. This is wrong. As a parent, you should let you kids no either way on the status of the tree. At least this would be a nice gesture. So, when your structure is complete you want to get it out to people.