what moveset should i be using on weaville. and do i take beat up or nightslash

All

In my opinion Beat Up / Ice Shard / Night Slash / +1 (Ice Punch, Metal Claw)

I would say that it depends how you run your team. If you are playing without entry hazards the moveset of xblazz10 (Beat Up / Ice Shard / Night Slash / Ice Punch) will do the job.

 

If you are playing Weavile as lead and intending to put entry hazards i dont see any use in ice shard. Weavile is one of the fastest Pokes ingame and can attack first in many cases or entry hazards will likely faint the opponents pokes in cases where ice shard would be useful. But you have to watch out for prio moves like Bullet Punch or Quick Attack.

 

So in case you are playing Weavile as lead and with entry hazards in your team i suggest the following moveset: Beat Up / Taunt / Night Slash / Ice Punch.

Taunt to annoy opponents with skarmory, forretress, tentacruel or donphan as lead.

With weavile, a combination of Beatup/Beatup/beatup and beatup is pretty strong. More seriously, if you lead with weavile beatup is the go to move, 100% of the weavile lead users I've seen are pretty much spamming this move (actually, I've seen one use ice shard once, but i think it was a missclick)