adding new disk >2TB, gpt?

[n dhert]

I have a running FreeBSD-8.2-amd system,
FreeBSD was installed in jan 2009 (then FreeBSD 7.0), which a fisk disk of
200 GB
for /, swap /usr /var /tmp.
Later that month, I added a 9 TB disk using /sbin/gpt
(since sysinstall uses bsdlabel/fdisk, it can't create disks larger than 2
TB)

I want to add an extra >2TB disk... and thought to use gpt again as I did in
the past ..

The FreeBSD book (in its 2011 version), section 18.3 still refers to using
gpt for disks >2TB
but the link gpt(8) leads to nowhere and /sbin/gpt no longer exists in
FreeBSD !

There seem to be two alternatives:
1) /sbin/gpart, of which the man page is quite similar to what gpt used to
be, but tells me
it is ''for disk partitoning GEOM class",
whereas gpt man pages (in 2009) said: gpt - "GUID partition table
maintenance utility".

2) a port sysutils/gdisk of which the Long Description says:
 "Edit GUID partition table (GPT) definitions in Linux, FreeBSD, MacOS X or
Windows"
but its web site shows a completely different command line interface, not
resembling the old gpt at all..

What is exactly that difference between GEOM and GUID ?
I'd like to have things as similar as possible ..
Can I use /sbin/gpart for the extra 9 GB disk ? or do I have to stick with
GUID and use gdisk ?