Should I send a blind copy of an email to myself, so that I have a record of it?

NO. NO. NO!

That’s extra work. That will create another email to handle.

If you want or need to save an item that you sent, go into your sent mail, as soon as it is sent, and do whatever you were going to do with that blind copied email. By doing it all in one sequence, you’ll finish the task and be able to move onto the next.