Whichever method you use, culture change is ultimately about the application of a consistent approach...my personal preference is the OCP because of the availability of robust web based tools that enable one to penetrate the organization to a much deeper level than is otherwise possible with a paper based model or an interview based model. This can be important if you are wanting to get at deeply rooted and/or problematic sub-cultures.
Smith
Dr. Michael BeitlerAuthor of "Strategic Organizational Change"