For my recipe, light trace is over 2 minutes with a stick blender. I watch my soap color. The color of the batter changes 3 times for me. My oils are tan colored and when I pour in the lye there is a color change to a more white color. Then, all of a sudden, it gets lighter again. When it gets lighter for a third time, drips will make an indent on the surface. That, for me, is light trace. I can swirl 2-3 colors in my slab mold at that point. Any further and I may get one color.