You need to create your own GPO template. There is a starter template at the link I gave you above. It is totally possible to set all of your printing preferences via GPO--just create a template and do it. However, you should still look at the Wizard first because that's easier and may do exactly what you want.
Certainly some security preferences are stored in the registry and in acrodata files. However, it is also certain that the password itself is set in each individual document.