Here's what ended up working for me.
1) Find the device number of your tablet. (For me, using a string as the device identifier didn't work. Using the device number seems to be the best way to go.)
$ xsetwacom --list --verbose
... Display is '(null)'.
... 'list' requested.
... Found device 'Virtual core XTEST pointer' (4).
... Found device 'Virtual core XTEST keyboard' (5).
... Found device 'Power Button' (6).
... Found device 'Video Bus' (7).
... Found device 'Power Button' (8).
... Found device 'Sleep Button' (9).
... Found device 'AT Translated Set 2 keyboard' (10).
... Found device 'Serial Wacom Tablet eraser' (11).
Serial Wacom Tablet eraser ERASER
... Found device 'Serial Wacom Tablet' (12).
Serial Wacom Tablet STYLUS
... Found device 'Macintosh mouse button emulation' (13).
... Found device 'SynPS/2 Synaptics TouchPad' (14).
2) Find the default/current values for your system.
$ cat /var/log/Xorg.0.log | grep "Serial Wacom Tablet:"
(**) Serial Wacom Tablet: Applying InputClass "Wacom serial class"
(II) Serial Wacom Tablet: type not specified, assuming 'stylus'.
(II) Serial Wacom Tablet: other types will be automatically added.
(**) Serial Wacom Tablet: always reports core events
(II) Serial Wacom Tablet: hotplugging dependent devices.
(II) Serial Wacom Tablet: hotplugging completed.
(--) Serial Wacom Tablet: top X=0 top Y=0 bottom X=30730 bottom Y=18520 resol X=2540 resol Y=2540
3) Tweak until you find good values.
$ xsetwacom set 12 TopX 60
4) Once you find good values, put them in /usr/lib/X11/xorg.conf.d/10-wacom.conf
Section "InputClass"
Identifier "Wacom serial class"
MatchProduct "Serial Wacom Tablet"
Driver "wacom"
Option "ForceDevice" "ISDV4"
Option "Button2" "3"
Option "TopX" "60"
Option "BottomX" "30690"
Option "TopY" "10"
Option "BottomY" "18350"
EndSection
Having to repeatedly reset the values is a little bit of a pain (more so than just writing down four numbers, anwyay) but it's not the end of the world.
2Don't forget that most convertible tablets are also a type of Wacom tablet. My Fujitsu Lifebook has a Wacom digitizer built in to the screen and, uncalibrated, it can be almost as much as an entire centimeter off at some positions. It's times like that when calibration really matters. – Adam – 2012-02-01T23:37:33.853