The tufts on your rear glass indicate attached flow. They're lying flat and relatively still. That's exactly what you want to see.
Separated flow is characterized by reversal of flow direction and/or tufts lifting clear off the surface while swirling randomly / violently.
For a clear example of flow separation revealed by tuft testing, watch the bottom row of tufts on the rear glass of this Toyota Corolla at around the 0:50 to 1:30 point in the video (the part of the video where there are NO vortex generators on the roof).
It is also possible to see a fair amount of turbulence, but still have attached flow (tufts move around with some side to side motion, but still continue to point in the
expected direction of flow).