The Yoda Technique for Buffing out a Car
Because some panels are not large and flat, especially on modern cars which are aerodynamic and for this reason very curved, then you use what I call the Yoda Technique
, that is you, "Let the panel be your guide"
(When you read the above sentence, use your best Yoda impersonation)
So of course, if you're working a long, thin panel then you might best work that panel by only going in one direction and doing your best to overlap your passes. Basically whatever it takes to get the job done.