From Diva's Husband -
She is sitting here claiming that neither side goes over or under - they sort of balance in the middle. She is sincerely convinced of it.
Unfortunately I think you will have to include this in your data.
I will attempt to monitor her behaviour in the future, and catch her with one thuumb over the other. I will fill you in if we can get a correction.
Myself - left thumb over right. Right handed.
Diva's Husband
I am literally sitting here crying with laughter hardly able to type.