I don't really understand what Kelly is saying about the first rib. It seems like when he's saying first rib, he's talking about the clavicle.
Personally, I think Kelly does some ridiculous looking stuff that could be vastly simplified. You can just stick your fingers in the area that Kelly is talking about, or you could use one of the curved self-massage tools. I can't think of any reason why you need to work that area with your arm overhead. While applying pressure, you can move your arm around if you want. It'll stretch and contract the area and provide a pumping type of action.
BTW. I have two cervical ribs, so I'm at a relatively high risk of developing thoracic outlet syndrome.