Thanks for the detailed reply with a sample which I was able to adapt to my contracts. I followed your guide and everything worked as planned! I would not have otherwise known to use firstname.lastname@example.org, so that was a big help.
One question I have is that it appears account 0 is used with oz send-tx by default. If I were deploying on a testnet, I would have to specify the --from (-f) argument. Is that correct?