https://pokemondb.net/pokebase/13440/what-is-a-good-moveset-for-liepard
This is about your question in this thread on a good Z-move using moveset for Liepard. I think that you should decide what ruleset(singles, doubles, etc.) you are going to play before making a competitive team instead of the other way around. I think that in the team you showed me, Liepard is not a very good Z-move user and you should give the Z-crystal to some other pokemon like Eevee or Zerora. I think that for singles you should give it the Prankster ability and use the below moveset.
Liepard @ Black Glasses
Ability: Prankster
EVs: 4 HP / 252 SpA / 252 Spe
Timid Nature
- Nasty Plot
- Dark Pulse
- Encore
- Copycat