The two are almost the same.
I aligned the ground plane of the template with the bottom of the model's wheels. I would have aligned the line at the top of the template with the top of the roof, but that would result in a discontinuity in slope where the hatch ends, due to Honda's slightly sharper curvature. The similarity in ground clearance is coincidence.
Here's what it looks like if your tail has a flat bottom:
The sides converge before too long, so there's no need to extend your curves beyond 60 inches or so.