Some newbie questions about yuls

I have some questions, hope you can help me:

- What is the best stance for PVE/PVP? I saw every Yul with sniper stance, I'm Ghost Sentinel and i've used Death eye stance till now but i dont know if i'm wrong using that stance

- At what level i can start to enchant my skills? The only skill i can enchant is Flash for now :<

- For PVP, Wizard harmony or Warrior harmony? I saw many yuls with wizard cause -20% cd but it's worth it in PVP?

- What dual-class skill you recommend for yuls?

Thanks a lot.