At 12 weeks, your kit might still be in the "bite it to find out what
it is" stage, but to make sure that he outgrows it, it sounds like
he'll need firm discipline.
 
The goal is to let your ferret know that he's been bad when he bites
(but of course to be as loving as possible otherwise!)  Ferrets range
from very insensitive to quite sensitive about discipline, so it can
be tricky to decide what kind of punishment is necessary.  Giz sounds
pretty insensitive, so I'd go with a punishment on the harsh end of
the spectrum, such as nose-flicking, which can be at least unpleasant
for almost any ferret if done hard enough.  Every time he bites, I'd
try to consistently flick hard enough to get him to sneeze once or
twice or to lick his nose or flinch.  Once he's gotten the idea that
flicking is punishment, you can lighten up.  For example, none of the
ferrets I've raised require more than a loud "No" anymore because they
associate "No" with some other punishment, such as a nose-tweak or a
time out.
 
Good Luck!
Dennis
P.S.  How far is Arvada from Colorado Springs?  I live in Monument,
CO right now.
[Posted in FML issue 1147]