Who do you know has been hung, let alone has had an option in the drop?
All that is mathematically worked out, and not an option for the one being hanged.
That's like asking the firing squad to shoot you in a particular spot; it just doesn't happen.
you only get a choice if you are hanging yourself. I have given this a lot of consideration and it would be my preferred method of suicide, there wouldn't be much of a drop - i'd just lower myself into unstoppable suffocation.