I have a pair each of 13/14s and 15/16s that are nothing special and that I have been using since the early '80s. Never saw any need to go better, They have held up just fine and work as well now as when new. I sometimes use a 17 for the locknut, but almost every locknut I've seen has been quite hard and ordinary crescent wrenches work just fine. Which ever is closer I use. I don't use the cone wrenches for the outside nut. Good chance of slipping and damaging the wrench.

Ben