I'm nearly six feet tall and I no longer can safely drive any car without putting the small round stick on blind spot mirrors. I've gotten so use to them I can't do without them. I never have to look over my shoulder to change lanes. I can see anything transitioning from the rear view mirror to the blind spot mirror.
I'm not sure if they would work for your wife but if she cannot see the blind spots without a sensor, I would be nervous to just depend on a sensor. Once the sensor goes off you still need to see what is in your way.
I have two Sonatas
2011 Sonata SE Nav, Iridescent Silver Blue Pearl
2011 Sonata GLS, Venician Red.