Re: Ikkyo vs elbow or bicep/shoulder
Elbow or just above. Allows for the manipulation of a pressurepoint on the outside of the 'knuckle' of the elbow, if need be.
Also I find it makes perfect sence body-mechanics wise. With the hand on the Biceps I would expect the technique to become more aggressive, but I have got much experience doing it that way though. Explore and deside for your self.