I don't understand the issue... the BMW steering wheel allows perfect 9 and 3 positioning. The "bumps" at 10 and 2 are meant to be above your thumbs or, in some cases, people lift their thumb a bit and rest it on the hump in the steering wheel. So, you grip at 9 and 3 (which also correspond to the paddles coincidentally
) with thumbs over the spokes and under the bumps on the rim of the wheel... perfect 9 and 3. Most, if not all, performance steering wheels are identical.
Here is a picture with a different steering wheel but with the same thumb bump and spoke design. On the BMW wheel, the thumb bump is a little more pronounced but it's the same thing...