Nelson,
I missed this thread the first time around. Do what Mike says. I leave the champfers shallow of the line, so I can go very aggressively if needed at first, then slow down and get more deliberate as I approach the line. If you've scored the line reasonable deep with the guage, you will get to a point where there is a thin sliver, just 1 or 2 shavings thick at the edge. Then that comes off, the only amount that is left is the thickness of the marking line. These pictures show what I'm talking about.