Wheel truing 101?

I have an older Trek being used as my commuter. It has an older, but
decent, wheelset on it with rim (V) brakes.

I've always noticed a major rub when braking on the front wheel. That
grab/release feeling when lightly applying the brakes. So I finally threw
it on the stand a couple of days ago and spun the wheel, looking for the
wow. I found and marked the chunk of rim that appeared to be the culprit
and grabbed my spoke wrench for my innaugural attempt at wheel truing.

The wow seemed to encompass about six inches of rim, so over that area I
gave the "wowed" (towards brake pd) side spokes a 1/4 turn loose and the
corresponding other side spokes a 1/4 turn tight. It seemed to work pretty
well, the wow was greatly reduced. I figured I'd ride it for a couple of
days and see how the stresses were redistributed.

Now it's a couple of days later, and the big wow is mostly gone. What I
notice now is a lot of little grab/releases. I'm assuming this is due to
minor wows in the rim that I didn't notice before because of the bigger
problem.

So, my wheel newbie questions:

Does working on one section of a wheel rim often/usually cause another
section to go out of true?
Is it worthwhile to try to get rid of all the little wows in the rim? I've
been using discs on my other bikes for years, so wheel perfection isn't an
issue there.
Is there a reasonable way for a newbie to judge correct spoke tension? I
have read a couple of articles by wheel experts, and it seems testing by
hand is almost an aquired art. Any tried and true simple methods
recommended?

Cheers
Gary