>tough claws
Boosts ice punch and knock off as well as low kick by 33%, does not help its priority
>technician
Boosts ice shard by a big 50%, sadly does not boost knock off, but also boosts the more gimmicky dark moves like punishment, pursuit and bite. Also the hypothetical icicle spear which outpowers even refrigerate double edge if it hits 5 times while also bypassing subs
>refrigerate
Only boosts fake out and double edge while leaving dark stab and coverage moves untouched. However double edge is a massive nuke that can OHKO even resists.
Tough claws is definitely the safe pick, boosting its main stabs and coverage. No benefits to its priority is upsetting though.
Technician is slightly more gimmicky, but still has plenty of benefits. Strongest ice shard in the game, strongest (and fastest) pursuit in the game, icicle spear is (potentially) a 187.5bp stab attack that goes through subs. And there's the ever gimmicky beat up.
Refrigerate is fucking powerful, but it reduces weavile down to switch in, nuke something.