Yeah, the trainers are pathetically easy. I don't know about number 3, but definitely get number 1 and 2. Don't worry about buying number 3 until after you get number 2 closed and feel whether or not you wanna move-up in grip strength.
Crushing strength is the wrong kind of grip strength for deadlifting and olympic lifts. Think about it you are basically 4 against 1, in other words you have the strength of 4 fingers against your thumb. If you plan on increasing holding strength then you must start with the weak link. If this interests anyone I can post more on the subject if not I'll save some typing