Well, I perused this thread waiting for kiddo at kindergarten, so I had plenty of driving left to figure it out.
10 and 2 did not last as long as driver's ed. I tend to go with one hand in the top half and one in the bottom. Seems to be a good combo, keep control at the top half, precision at the bottom half. Within that pattern, I vary a lot. Depends on the road, mostly. For bad weather, 9 is about perfect, right hand around 4 or so, but usually 2:30 and 7 or so. I often default to one-handed, even when I'm not doing anything with the other hand.
Maybe I'm careless, but it just seems to work better. I am ill-at-ease when symmetrical. On the morning drive, I'll often have left at 8 and hold kiddo's hand with the right. The joys of a small car