[brucepick]

This gets you out of covering over the rear lights, but I think it won't help much.

The curvature of the rear lights is a much smaller radius than the template. That is, if you use the template laid on its side to design a boattail in plan view. You would get this gently tapering tail shape. I'm convinced the air can't follow the inward curvature of the rear lights. So the flow detaches there. If you start your Kamm sides after that, the air is already doing its own thing, not following your side panel.

I believe the side panels would have to start where the lights begin and go rearward, at an angle that tapers inward only slightly. Just like the template tapers downward (or inward if you turn it horizontal) at only a very gentle curving slope.

You could try clear plastic, and use non-residue duct tape to attach it. 3M makes that tape, I got mine in a hardware store. Costs 2x to 3x the price of regular tape but I didn't want to ick up my pristine car (haha, you should see it!). For testing you can use cheap plexiglass. It will scratch but will be good enough for testing. Wrap the tape over the edges to protect the car's finish from the plastic. Then tape over that to stick it to the car.

Actually you'd need to start the side panels about an inch forward of the rear lights. Because you will cover about an inch of plastic with duct tape, to stick it to the car.