You hit the Nail right on the head.
The set below it are from matco, same thing just deeper and more of a selection.
I think that's going to be your easiest way to get that out. Be sure to use the one that feels like it barely wants to start on the bolt. Then Hammer the **** out of it.
Put your Biggest 3/8"ratchet on it and go to Strainin!! Lol