lmk

Pure java neither is gonna matter imo just use whatever has the better stats you need overall. Especially if you have infinity merc java is prob the quickest boss killer already so cb wont matter, and you should be able to 1-2 shot mobs so kb wont matter there either.

I am using Phoenix but still didnt find griffon . Decent kB gloves can be very helpfull i think

Crushing blow won't do much since it is reduced with ranged attacks.
There is 3 options that is generally used.
Magic = + 3 skill / attack speed
Rare = + 2 skill / attack speed / resistance / stats
Crafted = + 2 skill / attack speed / knock back / stats

Neither is really needed for pvm. Knockback in pvp has more uses, cb in pvp is dumb.