Right now I am trying to dump the database, gzip, move across, and import into the new slave (which is configured as a master to perform the initial setup). Ideally I do this dump, move and import during a period of inactivity on the master so the new server will come up and immediately be able to catch up on replication due to lack of activity. However, I have been importing the current db as a test and after 90 minutes it seems to have only got 2/3 of the way. I am not confident this will work but it seems like the most efficient way to start.
you can't use pg_dump to create a slave, as it won't have the same timeline.
I would use pg_basebackup, but in general streaming replication over a high latency erratic link will never work real well.
