If you will be making many OPs or posts that need to follow a similar template, you can create the template, send a PM to yourself and use the "label" feature to allow you to quickly locate the PM.
This is a work around. PM were not designed for that. Although it works, and it is a good idea, when the administrator think about solution he shouldn't think about workarounds.
What you are suggesting should be done in the drafts pages, not in a PM sent to yourself (which is like an autism solution, nobody should be able to PM yourself)