How to do incremental backup every hour in Postgres?

Question

Trying to do an hourly incremental backup of a single Postgres server (Win7 64).

I have the following setup in postgresql.conf:

max_wal_senders = 2
wal_level       = archive
archive_mode    = on
archive_command = 'copy "%p" "c:\\postgres\\foo\\%f"'

(restart)

I did a base backup with pg_basebackup -U postgres -D ..\foo -F t -x

Which made a big base.tar file in the foo folder and added some 16,384 KB files, which I assume are WALs.

What I don't understand is why the WALs in foo don't change. The WALs in data/pg_xlog change. Is pg not supposed to copy them over? How does it decide to do so?

Perhaps I need to set archive_timeout=3600 ?

I've seen several sites (pg's mailing lists, bacula's postgres page) that say you need to call pg_start_backup() and pg_stop_backup(), but I believe that those are not required. Is that true?

Secondary questions:

1. How often do the WALs in data/pg_xlog get written? What triggers a write?

   It seems to update a WAL if I do some DML then \q in psql. Or edit a table in pgAdmin then close the window. I figured it would write on commit.

2. Best practices? pg_basebackup once a week? Archive WALs to same machine as PG or a remote machine?