RE: compasses
Actually a Vanagon related subject I know something about.
Although not familiar with the specific compass you are referring to I'm
familiar with the general type, the small flux gate (or electronic)
compass.  I used to work for a firm here in Seattle that did virtually all
the compass adjustment/calibration for virtually every vessel on Puget
Sound, and that includes the carrier Abraham Lincoln.  Two members of the
staff were considered world experts on the compass.  I managed to absorb a
little information along the line.
First, the small flux gate compasses are VERY sensitive to position.  There
was one model of hand held that we refused to stock it was so prone to error
if not held absolutely level.  This translates into big errors if not
mounted exactly as the manufacturer instructs.  Newer models tend to be less
sensitive to this problem.  They are also much harder to compensate for or
adjust in a vehicle.
As for the good old fashioned magnetic compass, I have one of these mounted
dead center of the cover over my instrument cluster:
http://www.thecompassstore.com/51pilot.html
and it works perfect.  To my pleasant surprise it needed virtually no
adjustment when mounted in that location and has been working fine for five
years now.  Well damped, I've never had the various problems with it that
I've encountered over the years with other dash mounted compasses.
The compass at Target may well be a great unit but be warned that the small
flux gate compasses can be very temperamental.
YMMV