[..] I ran uncompressed pg_dump on multiple TB+ sized databases from v8.4 servers across the LAN using 9.6 binaries on the remote server. It was quite fast. Threading was key.
the "directory format" is the only format which supports parallel dumps, if I'm not reading it wrong.
How did threading solve "between database" dump/restore for you? Did you dump to "directory format" first, then restore? If so, then that requires quite a bit of temp-space...