Very good explanation guys.

Very old and very simpler way where you don't want much mess of commands,first of all copy .Session directory to desktop using any ftp client,create torrent of entire download directory using single udp tracker "udp://tracker.coppersurfer.tk:6969" make sure you select properly your pieces to be don't keep it automatic,if it's huge torrent I mean in terabytes select highest value you can or Google for piece size.

Just drop your newly created torrent file in new box.

Don't have to bother about installing any software or technically keeping busy yourself after ftp transfers.I am not saying they are bad methods but there is lot of technical hand require for it.

Infact ftp transfer is fast but I am not sure of disconnections issue and data corruption occurs if any.

Recently I transfered 3 TB data using torrent file,took me 27 hrs for transfer,but i didnt have to keep looking again and again or keep Amy machine running for it,i dont know about ftp how to work but my method you just drop torrent and leave it.

Post torrent completion delete torrent file from session directory and add your save session files from previous seedbox.very easy.