Freron MailMate

After some testing, I think this is sort of expected behavior, but it's not obvious that it would be at first.

I have some message links I saved to OmniFocus that aren't showing anything when clicked.
MailMate comes to the front, but no message comes up, no error is presented, nothing is logged.

I did some testing and I think the problem is that I used the OmniFocus command/script on messages that I had not yet sent.
Context: I like to create reminders in OmniFocus for important emails to follow up on, and at the time I'm sending a new message or reply is often the best time to set the reminder (instead of having to go find it after sending the message)
I believe the link being generated is to the draft, but that once the message is sent it gets a new ID...

Anyway:
1. Is there a way to check if the message is unsent, to stop the script from running/provide an error/warning?
2. Is there a way to set a script up that would send the message, then grab the correct URL, then run the script like normal?