Blog O' Matty >> Solaris ZFS
This blog has some various experiences and links of it's own. Actually the next two links here were obtained there.
ZFS Best Practices Guide
This page suggests that 3 disks use raidz and 5 disks use raidz2.
ZFS Management and Troubleshooting
Of importance at the top of this page, only Solaris 10 from 6/2006+ have ZFS. Also, they recommend 3-9 disks for Raid-Z pools. There is also info there on how to replace a drive. It says that Root pools (bootable) are not yet available as of 6/2006 -- but that once they are, they should be kept on a separate pool from the other data.
That last link also provided a link to:
Solaris ZFS Administration Guide