Any harness will do, really. We don’t even use the harness outside of the car. He does pretty well just being walked on his collar. He only ever pulls if he sees a squirrel. That’s one area where we’re working on training lol
I would be totally unsurprised to find out there’s some pit in there. He came from a shelter, and all the local shelters have tons of pits. His history before the shelter is a big question mark.