I like the Medium Turquoise. Here is a picture of my brother Tom and his first car, 67 Barracuda.
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View attachment 1715385294
Yeah I am liking the looks of the Medium Turquoise like on your Brother's Barracuda, it's got a little more blue in it giving it a bit more Blue Green look.
The Light Turquoise is going more to the light green family.
The '74 Dart G2 Frost Green above could use more blue in it too to make it look better.