Separate the setting from the behavior it controls
Start with the options a business user is allowed to change and the effect each has on the visitor experience. Model, language, size, position and button appearance may have different owners and validation rules. Agree the defaults and what happens when a value is unsupported. Keep presentation settings distinct from the agent's knowledge and action permissions. A useful configuration interface explains the consequence of a change and helps the user review it in the context where the widget will appear.
