In the past drivers were taught to keep their hands at 10 o’clock and 2 o’clock. Now it is advised to hold the steering wheel differently depending on your steering technique
Hand-to-Hand Steering: When using this method, your left hand grasps the wheel between 7 and 8 o’clock, and your right hand between 4 and 5 o’clock.
these changes were caused by the inclusion of airbags and steering wheels becoming smaller
it is also advised to not wrap your thumb around the steering wheel but instead keep it flush to the face of the steering wheel, because if you are in an accident and the air bag is deployed your thumb being wrapped can cause injury
https://www.nhtsa.gov/sites/nhtsa.gov/files/steeringtechniques.pdf
I do a single hand around noon.