Alternative method to scribe a trim line:

On a smooth flat surface, level and immobilize the fuselage (or any part for that matter) for initial or overlapping covering. A simple surface gauge with which to clamp a Sharpie at the desired height (like the union between the fuse sides and turtle deck) allows a line to be drawn around the entire part that will be as straight as your work surface is flat. Once this is done, you have a line to follow using this same trimming technique.




Simple surface gauge - used to mark a tube to length in this case - but is what would be used to mark any kind of part for a trim separation line after leveling the part -