I use my right eye. I write with my left hand but most other things, I do with my right hand.
OP - you said hand / eye dominance aren't always the same. In fact, they're often the opposites. A left hand part of the brain controls the right hand side of the body and vice versa*. The eyes aren't crossed like that so, right handed, left hand side of the brain dominates, left eye dominates. That's why people often say that use leftys are more artistic. That's because a different left-hand part of the brain controls creativity - the right is more logical.
Also, eye dominance isn't the only factor here as it may be easier to use a camera with one eye than the other. Maybe having your nose up against the LCD gives the camera a bit more stability?
I'd be interested to see the results of this too - do people use their dominant eye for the viewfinder?
Extend both hands forward of your body and place the hands together making a small triangle (approximately 1/2 to 3/4 inch per side) between your thumbs and the first knuckle.
With both eyes open, look through the triangle and center something such as a doorknob or the bullseye of a target in the triangle.
Close your left eye. If the object remains in view, you are right eye dominant. If your hands appear to move off the object and move to the left, then you are left eye dominant.
To validate the first test, look through the triangle and center the object again with both eyes open.
Close your right eye. If the object remains in view, you are left eye dominant. If your hands appear to move off the object and move to the right, then you are right eye dominant.