There no right or wrong to this, it all depends on personal preference based on the character of a dog you like, the ground you run and the way you hunt the quarry. For example I have a little whippet cross bitch that down here in devon killed a good number of hares before the ban but when taken to nofolk she didn't have the speed to even put a bend in a decent hare then on the opposite the bullx struggled to catch foxes on the small fields down here but would slaughter them on big ground