Entangled accounts are limited to 64 KB data blocks, and the proof of work for each block is costly. That imposes a practical limit of a few megabytes per message. The program will display a warning if someone tries to send too large a message to an Entangled account.
You can run your own server, and Entangled accounts work even if your server is down when the message was sent. You have to map a UDP port to your server through your firewall. Cick here for instructions on creating a server.
Set the "Retrieve email from" option to Entangled. No auth key is required. Enter one or more servers into the server list.
If you intend to receive a lot of emails, increase the number of mailslots so that the message announcements do not get too large.