I normally hold the steering tightly ( not too much) with two hands in 9-3 position. I lift my left hand only for changing gears etc. So far my knowledge is concerned two hand drive is safest one. My coach told me to hold it 10-2 position but afterwards I changed it to 9-3. I think taking a U-turn or cornering there is no hard and fast rule that how you will hold the wheel, it depends on your personal practice and comfort. But probably turning with palm in one hand is a bit risky one, specially for a newbie.