I would not encourage tourists to contact the iguanas by hand, but acclimating a small group for trained people to show would be acceptable. This would have to be a regulary handled group, so you are talking about starting at the hatchling stage, a large group and gradually choosing which to keep and others to let go.
If people wish to pet the iguanas it should happen only under restricted conditions with a proper handler holding the animal. Iguanas can cause some major bites, even the so called tame ones.. so always keep in mind they are wild animals. There is a dude on fb named ty park. Send him a message on how sorts his tamer candidates. Just give him a bit to respond he is a busy guy.