public vs member only

Hi folks

Hoping you can point me in the right direction. New to Rules. Seen Handbook, looked here in Groups.

Have a CCK form with a 2-choice selection field (Public vs Members Only) where I would like registered users to be able to choose if the node is created as a public one or viewable by members only.

I have got as far as giving the Rule a Label, selecting an Event (content is going to be saved), selecting the Condition as being related to the CCK field choice of Public and selection that the Action is Publish saved content.