Got some tuft testing in, and the results are interesting. there seems to be good attachment all the way down along the sides, but the middle is completely detached almost all the way up the hatch. The side attachment is most likely from vorticies.
Still image at 55 MPH:
Video at 65 MPH:
I also removed the OEM mudflaps and took some video of the Scangauge readings at 55 MPH, both on and off. I'll be uploading those videos soon, but here's the before and after pictures for the moment:
Before:
After:
The reduction in wind noise from the mudflap deletion is definitely noticeable. I decided to get some video after seeing my GPH reading stay pretty steady around 1.08, +/- a bit, when it was around 1.15 before.
EDIT:
Here's the videos from the testing:
Flaps on:
Flaps off: