Not really sure what you mean?
Our main application was never centered that I am aware of unless you actually constrain it in an html table through a header and footer. The ppopen template is this and there is a center statement there.
Content visible to verified customers only.
If your going to want to run the application at 80% my suggestion is to set reviewpost at 100% and wrap it in a table set to 80% that will ensure the sidebar will view correct etc.