>>Remember the Chevrolet Vega wagon? The one GM called the "Kammback?" That's what that was about. <<

No, that was just marketing. The rear glass of the Vega was still inclined at about 45 degrees AND it had a 2" high spoiler formed in the hatch above the glass. It was Kamm in name only.

You wanna' see a Kamm profile? look at a .50 cal projectile.
Kamm also demonstrated that the squared-off end could be about 50% of the frontal area, and he did some work about the radius between the taper and the blunt end.