It isn't clear from your question why you need to prove ownership. If you want to register copyright in the written material (use copyright.gov and obtain a registration for $35), none of these steps is necessary. Copyright ownership is the best evidence of ownership of written material and the form allows you to identify a pseudonym while listing your real name for ownership purposes.
Mailing a document to yourself is not evidence of anything - notarization is superior in every respect. Notarization does not verify the validity of the statement, only that the statement was sworn to on the date provided by the notary.
Answered on Mar 25th, 2014 at 4:21 PM