My argument is that self-defense is more narrow than your definition. At the point in the conversation when we were exchanging definitions of that term, no specific acts had been mentioned in the thread/post.
The threat of that particular CEO has now been neutralized. It was arguably legitimate at the time he was shot, tho.
The increased mass increases the force of gravity on the outer particles which ends up reducing the radius more than the increase due to the layer of new hydrogen, IIRC.