So I have asked a few people and we have come up with a "definition" of a proper head pass. Here are some quotes from anonoymous people...
Well, i think a head pass would be to throw ones head with one grabby hand to another, and have at least a little airtime.
I would say that a head pass is where the head is thrown, atleast an arms length between uke and tori, to be returned by the receiver's hand, gripped or otherwise.
In control of the head I agree with though. Maybe you have to be gripping it for 5 frames?
From these replys we can get a general sense of what a head pass is.
1. You must throw the head at least a legs length.
2. When you catch the head it must be gripped for 5 frames.
3. You must have control of the head when you catch it. (which simply is rule 2.)
If there is anything you would like to add or argue to remove please send me a pm(or post here) with the details. Thank you all for your cooperation.