Have you considered doing the the entire two-tone break line in a modest 1"-1.5" tall flame design? The black and silver colors could flow back and forth within the flames down the side of the car to still retain the body line.
I personally thing that the rear flames seem to take your eye off of the 69's killer lines rather than complimenting them.
I love flames and I really love two-tones as well..... anyway my .02
