Laughs - I should have been clearer. I was applying the kotegeishi using a combination of one of my hands and my forearm.
Ah. Yes, I noticed that in some of the examples.
Just to be clear about what I meant: I don't worry too much about either exact placement on uke's hand/forearm or the body part that nage uses to accomplish the turnover. If the body is in the right place it doesn't matter, and if it's not, manipulating uke's hand won't help.