You can steal my wife if you must, but touching the dog or truck will earn you a bullet
Seriously though, I would have done nothing different, except maybe not ask more than once.
If he is in my yard, on my property, I have no reason to assume he is not a threat.
I would have spotlighted the guy, asked once, THEN presented the weapon. IF he did not drop the dog and either surrender or run away I would have fired under the presumption that if he is on my property he has more than a dog on his mind, like my wife and two month old son.
Funny, since Aiden was born, I have become much more protective and MUCH less tolerant.