Question about a Prius Boattail Implementation

[aerohead]

Here's a plan-taper template which might help.I think your boat-tailing begins around half way across the rear wheels.

Also,here's the Gen-II Insight.Honda has relaxed the roofline,lofting it to the Template.The Prius V also has the lofted roofline.The V's Cd is higher,but it's roof is shorter.