gmirror + glabel + gjournal and 7.0 installation

[HN]

I'm about to install FreeBSD 7.0 on a machine with two equal sized
disks. I'd like to mirror these with gmirror and I think also I want to
use glabel to make things easier if (when !) one of the disks fails
and I replace it. I'm proposing to gmirror a slice and put the
partitions on the gmirror'ed slice. I think I'd like to use gjournal
as well.

Not entirely clear in my mind how to do this. I've got:

  http://people.freebsd.org/~rse/mirror/

for the mirroring, but don't have a grasp of how glabel and gjournal
fit into this.

Can I do this with sysinstall (should I ?) and what order should I be
adding things in ? Can I switch the journalling on and off after it's
been set up ? Any thing I should look out for ?

Thanks