I've been thinking about this a little bit in the last day or so, and for me, anywhere in "my pinch" is good. I often only have two fingers on the handle, with what could be described as a two finger pinch grip.
I think this is why I don't mind the weight being a cm in front, or a cm back of the choil.
So, the way I often grip a knife (depending on what I'm doing), if the balance is any where around my middle finger and forward, I'm happy.