1968 Barracuda Notch - Plano, TX

You mentioned that you liked the dark green metallic paint you found behind the splash pan.
That is very likely the F8 Dark Metallic green (or Ivy Green Poly depending on whether it was a Dodge or a Plymouth)that was on a LOT of Mopars in 68-70. You also said you might use a GM color because it was 'Readily Available'. I recently painted my 69 FB in the F8 Dark metallic green and I got my paint from a place called TCP Global (Tri Cities Paint. Look them up on the internet. They will mix any color from any car/year you want, and their prices are very Reasonable. I have used Dupont, PPG and other name brand paints, and I would compare their house brand (I bet it is a PPG product, since they are PPG dealers) to any paint I have ever used. Check out the results: