I have been building a helmet kit from far away creations, or MonCalsPropShop on Esty, and have recently come to the step when I need to paint the portion of the helmet underneath the respirator, where it should be black, but I cannot figure out a way to get a perfectly curved line along the center of the ridge, without going through complex processes that require a lot of guesswork, does anyone have any advice or information on what I should do. The website that has the instructions kind of skips over what I should do here, linked here: https://www.facebook.com/124196600929034/photos/a.3055973151084683/3055980477750617/?type=3&theater and I was hoping for some sort of help with this part.