Hi I am trying to repaint the GP38-2 into Norfolk Southern's new "Training First Responders" unit and I noticed the GP38 has two files one for the cabinets and one for the main long hood body and I am trying to make the "ribbons" on the unit but from what I see, I have to play a big guessing game and that is not a good way especially when I want the ribbons to have clean lines, any tips on how to repaint this nicely?
Here is what the loco looks like


