Since I hadn't driven a new Challenger till the day I went out to pick mine up, I wasn't aware how bad the right blind spot was till I was out in the middle of evening rush hour traffic. I couldn't see ANYTHING out of the right side. I had to pull over into a parking lot and figure out how to lower the headrests and move the right seat forward a bit. That cleared things up enough to be able to see out of the right rear side window.
Admittedly, even with the headrest down, the right blind spot is fairly large. But like with any car, you get used to this quirk fairly quickly and learn to compensate by using the right outside mirror A LOT.