I'm wondering about testing single cells, and wondering what to use for my standard peak threshold?

More importantly I want repeatable tests and fair comparisons. I'm wondering what determines when a nimh cell is "full"? If I use 5 mv for all cells are they full charged? or does something very terrible happen at 6 mv 7 or 8 mv?

I guess you can get the point to my question? when comparing cells, I could test the same cell 6 times and get 6 different capacities? which one is the true capacity?

The only ways I know iof are to use a standard temp , but I run into the same dilemma. The cell that I let charge to 135 is going to appear to have more capacity than the one I stop at 125 right? The other thing I can think of is to trickle the cell at a safe rate for too long a time and then I would know the cell is "full" but then is it possible to "overfill" it ?