about a martingle collar? We have the regular nylon collars, but both girls are needing new ones. I have never used one before and tried to read through prior threads about collars, but either i am skipping over them or the debate between harness and nylon are over-shadowing what is said about martingale's. Is it similiar to a "choke" collar (i hate that term, but...) but it is cloth? can someone who is experienced with the martingales please inform me?