Mailgun proxy for ghost

I am interested in using my self-hosted SMTP for sending newspapers.
After reading your post, the forum is suggesting me this related topic:

On that discussion thread people point out some problems, when trying to send a newspaper to 1000 addresses (for example). That is, it tries to send 1000 emails at the time that it is contacted by ghost, and the connection from ghost times out. So, it does not queue the ghost requests, and does not dispatch the email later, working on background, but tries to send them immediately. How does your proxy behave on this case?