Guys,
After my first poor attempt at cold bluing, I took all your advice in, used Imashooter's method (the touch-up was the rear sight dovetail - I installed a Skinner peep, removed factory notch rear sight, and unfortunately buggered the blank trying to fill in the empty dovetail slot). So, I used a small fine file, smoothed the blank down almost flush with the barrel, but unavoidably left a few scratches on the barrel. I taped off the area to be reblued, degreased as per Imashooter's instructions, heated barrel with hot hairdryer per Leveraddict, and used a cotton ball to put the bluing on the dovetail blank and adjacent barrel scratches. Then repeated 2 times, lightly buffing with 0000 steel wool between applications, and soaked a cloth in RemOil and BreakFree, laid on top of the barrel, and the next day, I can hardly tell where the professional bluing ends and my amateur bluing blends in...might degrease and try 1 or 2 more coats to make perfect, but it really looks great now, and no brown has appeared I would assume due to the heavy oil treatment.
Gunsmith I am apparently not, but you guys saved the day...Thanks! You are why I love MO!