>>2308804Is there is guide as to what color for the panel lining base on what color the pieces are?Use pencil.
Get a mechanical pencil that uses either .7mm or .5mm lead.
Looks far more natural than paint does, because it's more subtle and won't paint the walls of the panels, which can make the lines look uneven.
Only time that you'll want to use paint is if you're doing a wash (great for organic stuff) or if you're trying to panel line something really dark or want to give the appearance of a hole (barrel holes or barrel shrouds). In this case, you'll want to use black paint.
Panel lining is done mostly to imitate the shadows that naturally appear and the grime (oil, dust, etc) that builds up in those recessed areas, so you shouldn't use other colors to do so. It'll look cartoony or shiny (brand new), so do this if you want that sort of look.