help with pg_dump timings

I'm wondering, does anyone know of any timing tests for pg_dump?

I am trying to find the fastest way to do our nightly database backups using pg_dump.  And I just wanted to make sure I don't reinvent the wheel if someone has already done a bunch of comparisions with the various ways to backup.

Here are the kind of timings I'm looking at:

pg_dump -Fc -Zx
pg_dump -Fc
pg_dump -Ft
pg_dump
pg_dump -Fc | gzip > backup
pg_dump -Ft | gzip > backup
pg_dump | gzip > backup
pg_dump -Fc | bzip2 > backup
pg_dump -Ft | bzip2 > backup
pg_dump | bzip2 > backup

I know there are many variables, but I'm just looking at the pg_dump process.  Does anyone know what the fastest pg_dump would be?

Also, what -Z compression level equals the compression of gzip?  I've played with -Z9, but it seems to compress better than gzip (but takes a bit longer).

Thanks,

Chris