The air looks good!
The tufts on top behave very nicely (no surprise). The lower side (behind the wheel skirt) seems much less turbulent than when this was on the Civic.
Stills captured from the video...
Top, stopped at the side of the road;
Bottom at 80 km/h / 50 mph:
Another big difference from the Civic: the air likes the notch behind the tail light much more. Partly because I widened that section by about 1.5" on each side so it's a shallower cut-out; also possibly because the Prius tail light has a generous radius on the vertical edge, so flow wraps more easily into this area?
I dunno. All I know is aside from the tufts immediately behind the light, the rest are all streaming back, as hoped.