While my priorities have not changed a "shiny" moment had me read all about ZFS and how it will change the world, save all the children, and eliminate hunger for all time.
With advertisements like those, how could I resist trying to run it on a Compaq SR1103WM with a lofty 768MB of RAM? Luckily, I found a post which provided almost everything needed to do a ZFS-mostly install. As it had only been three days since the server rebuild, and everything I did to setup the server aspects (vs. the actual install and filessystem aspects) was still in my head, I figured it was now or when the next reinstall needed to be done. Needless to say I went with now.
Anywho, all the previous guidance regarding Rebuilding NAStie applies, but use the From sysinstall to ZFS-only configuration post to install. As I am limited on RAM I found the FreeBSD Wiki ZFS Tuning Guide particularly helpful (especially the settings from CyShubert). Also useful during the install and for the sake of research were Installing FreeBSD Root on ZFS (Mirror) using GPT and Chapter 4 of the Solaris ZFS Administration Guide.
To summarize, follow the instructions in the From sysinstall to ZFS-only configuration, use the loader.conf values from FreeBSD Wiki ZFS Tuning Guide, and use the rest of the links as reference and knowledge building.
Now to see how Samba likes serving files off of a ZFS platter.