F1 2018 Painting custom helmet in 3D - advice needed

F1 2018 The Game (Codemasters)
Dear all,

I'm attempting to create a custom helmet for fun, and I'm wondering what the best approach is to get straight lines on a helmet. I'm using jburon72 3D model (thanks for that) in Photoshop CC and what I do now is set the 3D model under an angle and use the line tool to create a line. That creates a layer you can merge down onto the 3D model. That works OK, but I'm wondering if there is an easier and more accurate way to do this. Disadvantage is that you cannot move the 3D model or the new line will not align how I want it to.

How do all the great artists approach this? Some advice (or resource) would be greatly appreciated.