Preferably I would like to create a dictionary dropdown property, customizable by the editor like Customer Group (see screenshot below) in the Contact edit view.

I've been able to create and display a string property by adding a row in Contact.[MC_BaseForm].xml with Control source="MyProperty" and initializing it in App_Start:

var customerMetadata = DataContext.Current.MetaModel.MetaClasses.Cast().First(mc => mc.Name == "Contact");

customerMetadata.CreateMetaField(
                    "MyProperty",
                    "My Property",
                    MetaFieldType.Text,
                    null);

Am I doing this correctly so far? How would I go about changing this property (or creating a new one) to display it as a dropdown?

Versions in Commerce Manager project: 

Thank you in advance.